I've always held the opinion--shared by the majority on this site--that Neil Walker is not a good candidate for an extension. Particularly since the Pirates obviously have to choose which of their players they want to invest in very wisely--given their financial constraints.
Walker's performance this season, as well as the second half of last season as lead me to reevaluate this position a bit. A couple of points to that end.
1) It's still early so all of this comes with the usual small sample size caveats but at the moment Walker is the 5th most valuable 2B offensively, per Fangraphs, but by far the worst defensively. The common wisdom is that defensive metrics require a larger sample than than 50 games to be useful and I accept that and assume that he'll eventually be rated as slightly below average (as he has been in seasons past) rather than terrible. But who knows. I've not watched quite as many games this year compared to seasons past but to my his performance in the field looks comparable to those prior seasons. Of course that can be hard to discern when your watching games via mlb.tv and somewhat sporadicly.
2) That Pedro Alvarez won't be with the Pirates after 2016 is I think something of a foregone conclusion that everyone accepts, right? Assuming you accept that the next question, with regard to Walker and an extension is could he play 3B? Currently in terms of offense he'd be the third most valuable 3B in MLB. Behind only Josh Donaldson and Todd Frazier (Donaldson it should be noted has been more than twice as valuable as Frazier thus far). It's probably safe to assume that guys like Beltre, Longoria, and David Wright will ultimately have more offensive value than Walker but even then he'd be in the upper echelon if his performance holds steady.
3) Walker has made some gradual improvements to his game in recent years. His K rate has declined almost every year for instance. Has he also improved his approach against LHP? That was obviously one of the biggest issues in years past and one of the main factors that would dissuade me from extending him. It's obviously hard to say based on sample size of 40 PA.
4) Walker has managed to stay healthy this season after missing time to injury in 2013 and 2012. His durability long term is another big factor when considering extending him.
I think his ability to hit LHP and his health are still open questions that require a bit more time to assess. That said if he remains healthy and improved versus LHP in a larger sample I think it might make sense to consider an extension, with the thought that you eventually move him to 3B. That doesn't account for his ability to handle 3B, a position he's not played in quite a while of course. And that unknown, his defensive value at 3B is obviously key to that scenario.
Of course Walker's super 2 status and his escalating salary via arbitration complicates the picture further. It may simply be two late for an extension to be mutually beneficial, financially speaking to both sides. An extension also not about how he's playing now but how he will play in his post arb years. Recent developments however have caused to me wonder if he might be--as a future 3B--more valuable in those aforementioned years than I previously thought.
Curious to hear what other folks think and if anyone has any thoughts on Walker's theoretical defense at 3B in particular.