The injury occurred in the fourth inning of Friday night's 4-1 victory over the Dodgers when Valentin fouled a pitch off his tibia.

"It went numb right away. As soon as I tried to walk back into the batter's box, I felt like something popped," Valentin said Friday. "It's not a complete break, just a little crack. But it's enough to get me out of the game for six weeks. It seems like everything happens in the same leg."

The switch-hitting Valentin was playing in his 29th game after missing 5½ weeks with a partially torn ligament in his right knee, which has been supported by a brace since his return. He had planned to put off surgery on his knee until after the season in part because of a $4.3 million team option for next year that would become guaranteed if he reached 400 plate appearances.

It now appears unlikely he will hit the mark.

"It's probably going to take me all the way until September to come back and play," said the switch-hitting Valentin, who is batting .240 with three homers, 18 RBIs in 166 at-bats spanning 51 games. "They're going to put a cast on it and I guess I have to be like that for six weeks. Hopefully the team can play well and give me a shot to be in the playoffs."

Valentin was on the disabled list three times before this season _ in 1997 due to a fractured left middle finger, in 1999 with a torn ligament in his left thumb, and in 2001 with a strained right hamstring.

"He's a gamer, he's always been a fighter, and no one feels as bad as I do about the situation he's in," manager Willie Randolph said. "Hopefully, he'll get back soon. I mean, if it's a six-week kind of deal, maybe he'll be back to help us out down the stretch. Anytime one of your players go down, you feel bad for him. But you've got to get past that and get ready for tomorrow."