PHOENIX -- Jeff Kent wasn't saying his season, not to mention his career, could be over. But watching him limp out of the clubhouse Friday night, it looked like a possibility.

Kent will undergo an MRI Saturday on his left knee, which locked up in so much pain that he couldn't take his at-bat in the seventh inning with Manny Ramirez on second base after a double and his Dodgers playing the D-backs, the team they need to beat.

At age 40, Kent didn't compile Hall of Fame credentials by backing away from those situations, so you know he's really hurt.

"I'm worried about it," said Kent, who as a rule dismisses the severity of almost every injury. "We'll get a picture and try to figure out what it is."

It's probably cartilage, but Kent said whatever it is, he's been playing with it for the past six weeks. Only in the bottom of the sixth inning, when Augie Oejda bounced sharply to first baseman James Loney, Kent took a first step toward his left and the discomfort he's been dealing with turned into severe pain.

"It just got the better of me today," he said. "There's a lot of clicking and popping and it's pretty painful. I try the best I can to play through it and deal with it, but it became unable to play."

Kent said he's been able to calm down the discomfort with a few days off and will try that again, but his return during this series is very doubtful. He was 0-for-2 with a walk Friday and is 5-for-32 on the trip.

"He's got a lot of things going on," manager Joe Torre said. "He's got a chronic issue with the knee. Stuff's floating around and it locked up. My guess is he won't play [Saturday]. He deals with a lot of stuff."

In that seventh-inning at-bat, pinch-hitter Blake DeWitt delivered an RBI single. DeWitt also ended the game with a strikeout.