The subject of contract extensions continues as the elephant in the locker room of the Pirates, who dearly want to retain control over the team’s engine.

It began with Jose Tabata in August 2011, GM Neal Huntington got his a month later, it continued with Andrew McCutchen last February and last week even Clint Hurdle got in on it.

So all eyes have fallen on Neil Walker, and possibly Pedro Alvarez.

But it may not happen any time soon for either — and not necessarily because of any foot-dragging by the front office. Rather, those players may not be gung-ho about getting locked into long-term contracts now.

These are purely my thoughts, no inside or outside sourcing, but  they are worth considering.

Walker would most certainly love security with his hometown team, but is in a unique situation. As the odd four-time arbitration guy thanks to Super Two status, he’s in line for three more substantial raises that would take a major preemptive offer to skirt.

The second baseman recently agreed to a $3.3 million pact for 2013, his first experience with arbitration. There is a predictable blueprint for that proces and, with that starting point, Walker stands to earn a total of about $23 million the next three seasons.

Very few Super Twos have gone through all four years of arbitration. Philadelphia second baseman Jimmy Rollins signed for $3.85 million in his second year of arbitration, then agreed to a five-year, $40 million deal in June 2005. But Rollins was 26 at the time; Walker already turns 28 late this season.

 To make it work with Alvarez, the Pirates might have to dramatically over-write and bump up one of the most team-friendly contracts around. This is a guy who is earning $700,000 this season after jacking 30 homers last year — and who would earn the same $700,000, the option still on the books, next season.

If the contract runs out as-is, at the end of it Alvarez would be only two years removed from free agency. At that point, he might prefer going through arbitration those two years, then hitting free agency.

Alvarez knows Alex Rodriguez is either out or well on his way to being out, and that the Yankees have no long-term solutions at third base. The New York native would love playing in the Bronx, and the Yankees would love having his left-handed power swing in the shadow of Yankee Stadium’s right-field porch.

We’ll see.