When the San Francisco Giants upgraded their first base situation by acquiring Ryan Garko on Tuesday, I wrote this:

The Giants had far bigger holes to fill at second base and shortstop, positions which thus far have combined for a .286 on-base percentage and .303 slugging percentage. They have found part of a solution to their middle-infield chasm in Juan Uribe (.280/.310/.431 on the season, .264/.309/.451 since getting regular playing time starting on June 26), but a trade for a middle infielder such as the Pirates' Freddy Sanchez would still have helped them far more than Garko will.

Wednesday evening, the Giants sent pitching prospect Tim Alderson to the Pirates for Sanchez. It would have been a better move had they not traded for Garko first.

There's no doubt that Sanchez represents a significant upgrade for the Giants. Their second basemen have hit .229/.285/.318 on the season while Sanchez has hit .296/.334/.442. A two-win player through the first two-thirds of the season per Baseball Prospectus's VORP, Sanchez could make the Giants as much as two wins better over the final two months given how far below replacement level his keystone predecessors have been. For a team nursing a half-game lead in the wild-card race, that could be the difference between giving Tim Lincecum and Matt Cain a chance to pitch them deep into October (a tall task given that the rotation of likely first-round opponent Philadelphia is now headed by dominating lefties Cole Hamels, Cliff Lee, and J.A. Happ) or having a full month to work on their Halloween costumes.

The reason I say this would have been a better trade had it come before and instead of the Garko trade is that Alderson was one of the team's top pitching prospects, as was Scott Barnes, who was sent to Cleveland for Garko. Neither is a true blue-chipper like Madison Bumgarner, but while it might have been worth trading one to put San Francisco in the playoffs for the first time since 2003 World Series, trading them both seems like too much to pay for what could prove to be a first-round exit at best.

With Lincecum (25), Cain (24), Jonathan Sanchez (26), Bumgardner (19) and Alderson (20) at Double-A and Barnes (21) backing them up, the Giants were ready to enter the next decade with a talented, deep, young, and entirely home-grown rotation. In two days they've sacrificed that depth for a shot at the playoffs with a team that, even with Garko and Sanchez, will struggle to score enough runs to reward its starters' fine work.

A modest upgrade at the plate and a downgrade in the field, Garko doesn't represent enough improvement for that sacrifice. Sanchez does, but in combination with the Garko deal, the Giants have likely gambled too much for too small a reward.

As for the Pirates, they've now traded their entire starting lineup from 2008, save for catcher Ryan Doumit, since last year's trading deadline. Now that he's off the disabled list, what are the odds that Doumit survives the week in Pittsburgh?