Why the A's swapped prospects

I couldn't figure out why the A's would so eagerly trade Brett Wallace, an outstanding young hitter who they just got from the Cardinals last summer. Well, to the rescue rides Susan Slusser. It was all about defense:

    Oakland obtained Wallace in the high-profile Matt Holliday deal with St. Louis in July, and though the team has no reservations about his bat, Wallace's defense was another matter. The A's apparently came to doubt the stocky Wallace's ability to play third at the big-league level, and the team already has plenty of young first basemen, including Daric Barton, Chris Carter and Sean Doolittle.

    In addition, the team recently acquired third baseman Jake Fox from the Cubs, and he is not considered a top-notch defensive player, either. Therefore, Oakland is planning to move second-base prospect Adrian Cardenas to third base full time, especially with Jemile Weeks, the team's top pick in the 2008 draft, performing well at second.

Until now, I wasn't even "on" Doolittle, but he's impressive, too. Oddly impressive. The 41st pick in the 2007 draft, Doolittle opened last season in Double-A and struggled. Nothing to worry about, really; he was only 21. But the A's didn't just not worry ... they pushed him to Triple-A, where he thrived.

Which isn't to say he's ready for the Big Show. That was only 28 games in Sacramento. But Doolittle does belong squarely in the group of young players who might well be good enough to play first base for the Athletics in 2011.

Cardenas is like Doolittle, but different. Like Doolittle, Cardenas is still quite young. Like Doolittle, Cardenas split last season between Double- and Triple-A. The difference is that Cardenas was impressive in Double-A before struggling in Triple-A. Still, he's just as much a prospect (if not more, since he's a year younger than Doolittle).

Essentially, the A's had too many young infielders and not enough young outfielders. So they traded a young infielder (or DH, eventually) for young outfielder Michael Taylor, who's not quite as young but has been far more impressive in the minors.

Meanwhile, the Blue Jays already had plenty of young outfielders; and maybe this means that Randy Ruiz will finally get a real chance in the majors. Unfortunately, the Blue Jays really are piling up a lot of guys at the wrong end of the defensive spectrum. In addition to Wallace and Ruiz, third basemen Edwin Encarnacion can't field a lick at third base, and corner outfielders Travis Snider and Adam Lind are little better.

Wallace might become a good first baseman. But keep an eye on the Blue Jays' defense. As they try to get back into contention, it's going to be an issue.