Meet Chris Duncan

The Red Sox raised a few eyebrows on Wednesday when they acquired outfielder Chris Duncan from the St. Louis Cardinals in exchange for Julio Lugo. The Red Sox had to pay Lugo's salary, of course, but a return of anything more than a couple of packs of bubble gum for Lugo seemed totally implausible when the shortstop was designated for assignment.

The deal for Duncan, of course, was only the second-biggest deal the Red Sox announced on Wednesday. But you can get all the analysis of that trade in Thursday's Union Leader.

The question we'll address here: Who is Chris Duncan?

The son of Cardinals pitching coach Dave Duncan and the brother of one-time Yankees cult hero Shelley Duncan, Chris Duncan made his major-league debut in 2005 and has had more than 200 at-bats in a season four times since then. He has spent the entire season with the Cardinals this season, hitting .227 with a .329 on-base percentage and a .358 slugging percentage.

The 28-year-old outfielder's best season was 2006 -- he hit .293 and OBP'ed .363 that season to go along with 22 home runs, and he even hit a home run in the National League Championship Series against the New York Mets.

Since then, though, he's become mostly a platoon player who played almost exclusively against righthanded hitters. He spent most of the second half last season on the disabled list with a pinched nerve and, later, recovering from surgery to address a herniated disc in his neck. It's easy to attribute his career-low batting average to his neck and back woes, but there's no way of knowing how severe the effects will continue to be.

The key is to look at his platoon splits:

Minor leagues (four seasons)
vs. LHP: .233/.333/.425
vs. RHP: .270/.363/.461

2007
vs. LHP: .213/.289/.313
vs. RHP: .271/.371/.525

2008
vs. LHP: .147/.194//294
vs. RHP: .266/.371/.378

2009
vs. LHP: .231/.296/.354
vs. RHP: .226/.339/.344

(It's probably small sample size, but it'll be interesting to monitor the leveling out of his splits this season.)

The trade for Duncan appears to have quite a bit to do with the trade for LaRoche announced earlier in the day. Duncan was assigned to Triple-A Pawtucket, and there he'll stay until the Red Sox need him.

But his acquisition would allow the Red Sox to release Mark Kotsay to make room for lefthanded-hitting first baseman Adam LaRoche. Kotsay has played primarily first base this season and thus seems to be a superfluous player at this point -- except that he can play in the outfield, too. He just hasn't played there much this season. (Part of the reason for that: He's a lefthanded hitter, and that means he doesn't fit well with what the Red Sox want to accomplish when they rest J.D. Drew or Jacoby Ellsbury.)

Should Mike Lowell land on the disabled list and LaRoche become the Red Sox's full-time first baseman, they'll need a lefthanded bat off the bench. Should Drew or Ellsbury get hurt, they'll need a lefthanded-hitting outfielder. In either case, they'll be summoning Duncan.