This seems to be an idea the Cubs are considering. I guess I'm in favor. Baker is demolishing lefties, but the better comparison is Darwin Barney. Barney, who has previously sat vs lefties will enter the lineup at second while Baker shifts to first. The comparison is only vs lefties, since Pena will still play vs righties.
Defensively this has to be an improvement. Pena's defense isn't bad, but Baker is good at second, should be better at first (it's easier) and Barney is probably better than Baker at second.
Barney would likely do better against lefties than he would against righties, and he's doing pretty good against righties. It's hard to say what he'll do exactly as he continues to play, but as long as he's doing good he's doing good.
It's just 13 at bats vs lefties for Pena, but he has been attrocious. I'm going to go into wOBA (which is a combination of all different types of hits). Average wOBA is around .320 to .330, Pena over the last 3 years has been .305, .352, and .300. A below average hitter 2 of 3 years.
So not only should Pena be platooned, he should have been platooned in 2010 and 2008. So I'll go on record saying I support this.
I fully expect Pena to rebound going forward, but more against righties than lefties. As long as Barney is hitting, he should be in.