So what was the unlikeliest thing about the walk-off homer that gave the Pirates a 4-3 win Tuesday night?

That Josh Harrison hit it?

No — that a Marlins pitcher gave it up. The Miami staff had been riding the Majors’ longest streak since 1998 of not allowing a homer — 13 straight games, since Todd Helton went yard on Jose Fernandez in the second inning on July 23 in Denver. ..

The Pirates know all about keeping it in the yard: They’ve allowed four homers at home in the last 24 games and 227 innings. …

Gotta love Andrew McCutchen making perhaps his best catch of the season — that diving grab of Adeiny Hechevarria’s liner in the seventh — then saying, “I feel like I made it look fairly easy.” … 

I wish Jeff Karstens, who has such a bond with Pittsburgh fans, could be a part of this. He wishes, too: “It’s killing me to have to watch this, but it’s still fun.” … 

Since a five-game stretch in which they fanned 62 times, the Bucs have cut down their whiffs to an average of six in their last nine games. … 

Manager Clint Hurdle didn’t use the words “Magic” or “Destiny,” but he came close after Tuesday’s game.

McCutchen makes a flying catch to avert disaster … Jeff Mathis’ drive into the right-field corner later in the seventh with the bases loaded barely curves foul, missing the line by five inches … the Bucs flop in a bases-loaded, none out situation in the eighth and live to tell about it.

“Those are little things that make you go, ‘Yeah, something’s going on,'” Hurdle said. … 

If the Pirates take the ongoing second game of their doubleheader with the Cardinals and increase their NL Central lead to a game-and-a-half and their record to 22 games over .500 — I think Neal Huntington will sit out this Trade Deadline.

Could you blame him?

A year ago, the Bucs were at their 16-games-over-.500 peak at the Deadline, and we know where Huntington’s dealing got them thereafter.

If you are the Pirates GM, do you risk making moves with the club again at its season peak of 22 over? Could you even bear the thought of the moves again misfiring?

I think not. If a no-brainer move presents itself, one so obviously advantageous that even having it backfire would not be laid at Huntington’s feet, sure. But no such players appear available in the current market.

Otherwise, he will not be in a mood to hazard the club’s obvious feel-and-play-good vibes on anything marginal. And any criticism of that would be unfair.

When you own the best record in the Major Leagues, “status quo” does take on a different meaning. 

This is where the Pirates will really miss Wandy Rodriguez.

Much has been made, justly so, of the Bucs’ depth in starters. After all, they went through 11 of them fairly early this season, without missing a beat.

However, being able to start three left-handers in the five-game series that begins tonight with the Cardinals would be a tremendous advantage for the Pirates — and packing three southpaws would continue to be an edge down a stretch in which the Bucs will play 20 of their remaining 59 games against the Cardinals and the Reds.

St. Louis has a record of 11-13 against left-handed starters — a remarkable outtake for a team with the Majors’ best record. The reasons for that are hard to isolate; both second basemen (Chris Carpenter, Daniel Descalso) and center fielder Jon Jay are lefty hitters and switcher Carlos Beltran definitely has more pop from the left side. But a team with Allen Craig, Matt Holliday and Yadier Molina still has most of its firepower on the right side.

It could simply be the novelty; the rotations of most teams do not have multiple southpaws.

Whatever, being able to throw three lefties at St. Louis would be a plus. Same, incidentally, for Cincinnati down the road: At 19-19 against lefties, the Reds aren’t much better.

The Bucs are leading with Francisco Liriano tonight, and have Jeff Locke on tap for Wednesday. Two is good. Three would be better — so it would not be surprising if GM Neal Huntington is going down to the Trade Deadline shopping for a lefty arm.

Barring an acquisition, the unannounced starter for Game Two of tomorrow night’s doubleheader could be a lefty recalled from Indianapolis. Best bet Kris Johnson — who is 9-4 with a 2.44 ERA — is out after going seven innings on Saturday. Another option is Andy Oliver, who has not been as consistent (5-3, 3.97) but is well rested.

Would Clint Hurdle consider giving the spot start to Justin Wilson, rather than Jeanmar Gomez? Possibility.

In 40 years of covering Major League Baseball, seldom have I seen a scene as depressing as Jason Grilli fighting back tears as he left the Nationals Park mound last night.

He was two strikes from his NL-leading 31st save, which has made him so critical to the charge of the Pirates, who at the time were gasping to hang onto a 6-5 lead over the Nationals in another game critical to chilling out a fan base prone to collapse-dreading panic.

But this wasn’t about the team. The Bucs have the bullpen arms to adjust on the fly, from Mark Melancon down.

This was about the man, a man who has overcome so much — others’ skepticism, his own physical woes — to, at 36, validate a lifetime of faith and perseverance. Imagine doing something for the first time in your career at 36, and becoming the absolute best in your profession at it.

Professional, and personal, gratification does not get better than that.

And to have it all unravel on one fateful, pain-inducing pitch is so cruel.

We don’t know what tests on Grilli’s forearm will reveal. In tweets this morning, long hours after letting the shock of the trauma wear off, Grilli himself referred to the episode as a “minor setback.”

Regardless of those medicals, even if they do not indicate any structural damage, Grilli obviously will be out of action for a considerable time.

The Pirates will overcome his loss. Here is a fervent prayer that Jason can get over the bad deal, too.

I seem to recall a movie a few years ago titled, “Death By Chocolate,” or some such mixed metaphor. I don’t know what it was about, but I’m pretty sure if the Pirates don’t sweeten their situational hitting, they could fall on their sword.

In other words, there is something to the notion of having too much of a good thing. Also — live by the sword, die by the sword. The Bucs’ first-half pitching has been so phenomenal — starting or relief, you name it — they have to fight the temptation to continue depending on it.

Hope GM Neal Huntington and manager Clint Hurdle put up a good fight: One, it isn’t reasonable to expect the staff to remain on its records-busting course down the hot stretch; two, even if the pitchers pulled it off, would it be enough?

Just look at the last nine games into the All-Star Game break: The Bucs did not give up more than four runs in any of them, yet could win only four of the nine games.

It’s mind-boggling that the Pirates are within a game of the NL Central lead, despite hitting more than a hundred points lower with men in scoring position than the Cardinals (.230 to .337).

I watched Sunday night’s Cards-Cubs game, naturally curious whether a St. Louis loss would send the Bucs into the break tied for the division lead. It was both impressive and disconcerting to watch the Cardinals produce wave after wave of clutch hits to quickly respond every time the Cubs came back in the game.

We haven’t seen the Pirates show anything like that yet. They’ll need it. Of their remaining 69 games, 20 percent will be against the Cardinals. Pitching alone is not going to take them.

Do you hold out faith that the guys in-house become more productive at crunch-time? Or do you get some significant new guys in house? Do you read them the (Alexis) Rios Act?

Looks like Mark Melancon — originally one of the most glaring omissions from the NL All-Star Team — is being added as the replacement for his own teammate, Jeff Locke.

No formal announcement yet — but Clint Hurdle had an amusing Freudian Slip moment in his pre-game meeting with the media. In discussing the communication between the All-Star manager and team managers of the All-Stars, Hurdle said, “I’ve already had conversations with Bochy about what’s acceptable use for Melancon.” 

The Buccos skipper then quickly backed off from that, making it sound like a generic reference to possible All-Star pitchers.

“If you’re sharp and yo want to be first — go with it … but you want to make sure it’s corrector,” Hurdle said with a twinkle in his eye when it was pointed out what he had inadvertently said.

The posturing is sensible. All-Star team managers deserve the right to make their own announcements regarding roster makeup.

Looks like all the signs and rancor Pirates fans have worked up for the weekend over National League Home Run Derby captain David Wright’s exclusion of Pedro Alvarez will go to waste.

Alvarez has been added to the NL foursome for Monday night’s 2013 Chevrolet Home Run Derby as a replacement for Carlos Gonzalez, who has withdrawn due to a sprain of his right middle finger suffered earlier this week.

Alvarez, whose original omission despite ranking second in the NL with 23 homers — one behind Gonzalez — drew the ire of fans and puzzled teammates, thus will become the fifth Pittsburgh player to participate in the Derby.

And the Bronx native, a first-time All-Star, will get to do it in his hometown, in Citi Field.

Alvarez is the latest addition to the list of Pirates that includes Bobby Bonilla (1990), Barry Bonds (1992), Jason Bay (1995) and Andrew McCutchen (last season).

Wright, coming to town with the Mets for the weekend series against the Bucs that will close out first-half play, had been bracing for a rude welcome from PNC Park after he had filled out his Home Run Derby field with boyhood buddy Michael Cuddyer, also of the Rockies, and Bryce Harper in addition to Gonzalez.

Nomar Garciaparra, the former All-Star infielder who will be involved in ESPN’s coverage of the Home Run Derby, recently addressed the heat Wright could have expected from Pittsburgh faithful.

“But I think David Wright has thick skin, huge shoulders and is confident and he explained why he picked the guys he did,” Garciaparra had said.  

Explanations were replaced by deed on Thursday as, in the view of many, justice was served. Alvarez, coming into his own as an overall offensive threat, has totaled 45 home runs in his last 174 games, since the middle of June ’12.

I’m sure you’ve noticed the recent assault on existing pre-All-Star-Game records. We’re in record-pace overdrive. We’re bombarded daily with so-and-so setting such-and-such records for first-half production.

Nothing against the truly unique performers doing these deeds — but what a crock.

Record productions before the All-Star break? Gimme a break! Talk about arbitrary.

The date of the annual All-Star Game is a variable, and because the 2013 Midsummer Classic comes unusually late, 93 games will have been played before the sport goes on brief hiatus. So all these benchmarks are taking advantage of far more games than typical.

I’ll give you just two examples, but the relative unbalance holds for every instance of “record” performance:

Baltimore’s truly gifted third baseman Manny Machado is up to 122 hits. Which, we are told, ties Al Kaline for most prior to the All-Star Game by a player in his age-20 season.

Fine. Machado has already played in 90 games, with a week to go. When he set that record in 1955, Kaline’s first-half consisted of 81 games.

Another, also featuring Machado: He has 39 doubles, within three of Edgar Martinez’s pre-break record set in 1996 — when the Seattle DH played in 85 games before the break.

You get the idea. For the most part, we’re comparing apples and oranges. They are both round — about all they have in common.

A.J. Burnett will get back on his horse, in ballplayer-speak, right where he dismounted.

The Pirates’ ace right-hander will come off the disabled list to start Sunday’s series finale here against the Cubs. It will be his first appearance since he went 8 1/3 innings in Wrigley Field for a 6-2 victory on June 8.

Five days after that victory, giving him a lifetime record of 5-0 in Wrigley Field, Burnett had to go on the DL with a Grade 1 calf-muscle tear suffered during routine running drills in PNC Park. 

He resumed throwing days later and, considering there was no injury to his arm, little thought was given to having him detour fir a Minor League rehab assignment prior to rejoining the rotation.

“His last bullpen, his timing and rhythm were really sharp. We didn’t see a need to have him throw 75 pitches in a rehab game,” manager clint Hurdle said. “His experience, the adrenaline of a packed house, his success here — all of it will combine to get him out there in a very competitive state.”

“Everything feels good. I’ve been doing a lot of PFP (pitchers fielding practice,” said Burnett, addressing the concern of being able to leave the mound for fielding plays.

The last time he threw a pith for them, the Pirates were in second place in the NL Central, trailing the Cardinals by three games. The bucs took a two-game division lead over St. Louis into Friday’s action.

“It’s been fun to watch. I’ve been involved every step of the way, and I can’t wait to contribute,” said Burnett, adding of making his comeback in Wrigley Field, “Any place would be good — but I do enjoy pitching here.”

The brilliant depth and performances that have carried the Pirates to the top of the Major League standings is the half-full cup of Buccos pitching.

But the part of the cup that is half empty is about to crack.

Wandy Rodriguez and James McDonald are both dealing with setbacks certain to shelve them for a long time. A.J. Burnett, another sidelined member of the season-opening rotation, is making good progress back from the torn left-calf muscle that landed him on the DL two weeks ago.

Rodriguez experienced tightness in his left forearm while doing some flat-ground throwing on Friday, has been shut down and has an appointment with the team’s medical staff. It is the same condition that forced him out of a June 5 start in Atlanta and onto the DL.

McDonald will see Dr. Keith Meister in Dallas on Tuesday for confirmation of diagnosis of the source of his shoulder discomfort  by team doctors. McDonald declined to disclose that diagnosis, characterizing it as premature.

If Dr. Meister’s findings differ, McDonald plans to seek a third opinion from Dr. James Andrews. Otherwise, he will turn his attention to curing the condition that has ailed him all year.

“I’m eager to find out just what’s going on,” said McDonald, who conceded not having felt right even while being part of the Pirates’ regular rotation through April. “At the beginning, there really was no pain, it just felt different. Then when it started to hurt, i thought, ‘There’s something wrong. We’ve got to look at this.'”

McDonald was on a conservative throwing program until starting a Minor League rehab assignment on May 27.

“After not throwing for a while, my first couple times out, I felt fine,” McDonald said. “Then the same pattern started over again, where I couldn’t get loose and had the discomfort.”

McDonald made the last of his six rehab starts on June 22.

On the positive side, Burnett had a problem-free 38-pitch bullpen session on Friday. On Tuesday, he will throw a simulated game spiced with elements of his biggest challenge, the ability to charge off the mounds to field the position.