David Wells said he will abruptly pull the plug on his 20th and final major league season if his knee problems do not start to improve or if he discovers that he is risking his future health by continuing to pitch. The veteran left-hander, who is one month shy of his 43rd birthday, said his right knee is bothering him so much that he ?struggled? to play catch prior to last night?s game. He was due to receive the second of three weekly injections of a synthetic lubricant for the joint yesterday but said he fears the lack of remaining cartilage in the knee may make the procedure a lost cause. ?If (the Synvisc injections) don?t work, I don?t pitch and you go home,? Wells said. ?That?s the only thing you can do. You can stick around for a moral support-type of thing, but it sucks. It drives you batty when you?re not able to go out there and pitch and contribute.?