Maybe he wasn't that good to begin with. Ever think about that? He fought a bunch of guys that just layed down until he met Green, and we all saw what happened then. Green might have ruined him, Bika might have or maybe he was never that good to begin with who knows? He should keep fighting though he's an exciting fighter win or lose.
Besides his chin, Codrington's legs aren't there anymore and he doesn't have a different style to prolong his career. Straight-up style, with some power, but little head movement, and it will be rare to see him "outbox" somebody to a comfortable win. Another fight with a nice record, who will cash out after a couple of easy wins.