Let's look at their Win Shares and their WARP1 scores from Baseball Prospectus, along with a few other candidates.
Player WS* WARP** Pujols 35 11.8 Ludwick 26 8.3 H.Ramirez 32 7.3 Uggla 25 5.7 C.Jones 24 8.4 Berkman 38 9.5 Wright 29 7.5 Reyes 29 5.5 Beltran 33 6.5 Utley 30 7.0 Howard 25 3.4 Rollins 24 4.1 Holliday 23 7.1 M.Ramirez 34 8.6 Ethier 25 4.5 A.Gonzalez 26 6.6 McLouth 25 3.9 Fielder 23 4.3 Braun 25 6.7 D.Lee 18 5.7 A.Ramirez 25 4.7 DeRosa 23 5.6 J.Santana 21 8.6 Lincecum 27 9.5 Dempster 18 7.5 Hamels 18 7.8 Webb 22 8.7 Haren 20 8.3 Sabathia 25 10.7
*Source: The Hardball Times
**Source: Baseball Prospectus. I use FRAA, instead of FRAR, so the WARP1 number is converted. That hurts some players more than others. For instance, it takes 2.2 WARP away from Hanley Ramirez, since he is better than replacement, but below average.
Pujols runs away with it. His 11.8 WARP1 number (with my fielding adjustment) is a big big number. The best of Pujols career.
I think he's going to win it, but I think the Howard and Fielder bandwagons are strong. The fact is, of those three guys, only one guy did it consistently all year.
Howard didn't heat up until September. Had he played to his capabilities, the Phillies would have run away with the East instead of clinching just before the season ended. Also, check out some of the other numbers on the Phillies. Jayson Werth and Jimmy Rollins were extremely valuable down the stretch too.
Last year Rollins won it and I thought he was fifth. If Howard wins it, it is much more of a travesty. He doesn't even belong in the discussion. Let's put this in perspective: Ryan Howard was about half as good as Ryan Ludwick.
I think it is totally appropriate to include Manny in the discussion, even though more than 1/2 of his season was in the AL. The AL/NL distinction means very little anymore. Manny is almost single-handedly responsible for the Dodgers making the playoffs, and more than half of his numbers above came in the NL.
Here's a table with a composite score, which I described in my NL Catcher's post, assuming the replacement WS for a player is 5.
Player Composite Pujols 65.4 Berkman 61.4 M.Ramirez 54.8 Sabathia 52.1 Lincecum 50.5 H.Ramirez 48.9 Beltran 46.5 Wright 46.5 Utley 46.0 Ludwick 45.9 C.Jones 44.2 Webb 43.1 J.Santana 41.8 A.Gonzalez 40.8 Reyes 40.5 Braun 40.1 Haren 40.2 Holliday 39.3 Uggla 37.1 Hamels 36.4 Dempster 35.5 DeRosa 34.8 A.Ramirez 34.1 Ethier 33.5 McLouth 31.7 Rollins 31.3 Fielder 30.9 Howard 30.2 D.Lee 30.1
Assuming pitchers aren't eligible (b/c they never win and they have their own award), Pujols gets it easily, with Berkman second. I'll give third to Hanley, since Manny split leagues, with Manny 4th and the surprising Ryan Ludwick 5th. I'm ignoring the Mets before Ludwick, since they collapsed at the end. Again.