Tom Szczerbowski/US PresswireMarcus ThamesAdding to their collection of poor-defending but slugging outfielders, the Dodgers are poised to sign the guy who might be Jay Gibbons' brother from another mother: Marcus Thames. Tony Jackson of ESPNLosAngeles.com has details.Thames, 34 in March and four days younger than Gibbons,  had a .350 on-base percentage and .491 slugging percentage against lefties last season, making him a potential platoon partner with Gibbons or Xavier Paul (only if the latter has a knockout Spring Training, it appears). Overall, Thames has an OPS of .802 in a career spent entirely in the American League. But Thames carries with him the baggage of being yet another left fielder that Dodger pitchers might be afraid of.The Thames signing reduces the chances of the Dod