The Fall of Piazza Could Be Costly : Dodgers: Catcher may be out two weeks after injuring thumb while running bases. Karros leads 3-1 victory.

Dodger all-star catcher Mike Piazza suffered a torn ligament in his left thumb Wednesday and is expected to be out 10 days to two weeks.

Piazza was informed of the diagnosis Wednesday night after the Dodgers’ 3-1 afternoon victory over the San Diego Padres and is scheduled to undergo an MRI test today to confirm there is no fracture. Yet, he was told he will miss a minimum of 10 days and is expected to be put on the 15-day disabled list.

“I know one thing, man,” Dodger Manager Tom Lasorda said, “it’s going to be tough losing that guy. He’s a huge asset. He can ignite our whole offense.

“There are only a few guys in baseball who can carry a ballclub. We’ve had our share with guys like (Steve) Garvey, Reggie (Smith), Penguin (Ron Cey) and Dusty (Baker), but you can put Mike right there with those guys.

“It’s going to be tough without him, but we’re just going to have to work that much harder while he’s out.”

Piazza, who sat out four games this season because of a strained right hamstring, is batting .537, which would lead the league if he had enough at-bats, with four homers and 13 runs batted in. He was batting .640 the last six games.

It was his near-home run in the first inning Wednesday that resulted in the injury. Piazza, batting with one out and Garey Ingram on second and Raul Mondesi on first, hit a vicious line drive off former Dodger Fernando Valenzuela toward the right-field fence.

Everyone figured it was a home run, including Piazza. Instead, the ball hit the orange piping off the top of the fence and bounced back onto the field. Piazza, watching the ball, stumbled as he rounded first and braced his fall with his left hand.

Piazza stayed in the game and caught the bottom of the first inning, but the pain forced him out of the game the next inning. His thumb was put in a splint, and he flew to Los Angeles for X-rays. It showed no fracture, but Piazza was told that he suffered a torn ligament.

Carlos Hernandez, batting .056 this season without an extra-base hit, will replace Piazza in the lineup. First baseman Eric Karros, who’s batting a league-leading .475 with 17 RBIs, will moved into the cleanup spot.

Karros, who went three for four with a homer and two RBIs, was the hero Wednesday. He vowed revenge after being hit with a pitch Tuesday night, and delivered on his promise, driving in a run in the first inning and hitting a solo homer in the ninth.

“It was very gratifying, I’ll say that,” Karros said. “Whether that guy (reliever Bryce Florie) did it on purpose or not, I didn’t like it one bit.

“All I know is that it was pretty ironic that the one pitch that got away from him happened in that situation.”

The incident occurred after Piazza’s home run in the the eighth inning Tuesday of their 9-2 loss. The next pitch by Florie came toward Karros’ head. It hit Karros’ left elbow, knocking him to the ground.

“It was ironic that was his only wild pitch of the game,” Karros said. “I didn’t say anything, but believe me, I remembered.”

Florie and the Padres deny that it was a purpose pitch and pointed out that Florie has walked nine batters in eight innings. Yet the Dodgers still were talking about it Wednesday morning and before batting practice had a closed-door team meeting.

The Dodgers were reminded to play aggressively, told to shrug off their play of the previous two nights and promptly knocked around an old friend.

Valenzuela, realizing he might have been pitching his final game for the Padres, was the victim of the Dodgers’ aggression. The Dodgers scored two first-inning runs and were within one hit of knocking Valenzuela out of the game right then.

“It was typical Fernando,” Karros said. “He’s the type of guy you think you’re going to rip, and then you can never hit him hard.”

Indeed, after the first inning, he looked like the Fernando of old. He became unhittable, retiring seven consecutive batters and giving up one other hit during his five-inning stint. He wound up yielding only four hits and two earned runs, and who knows, might have received a stay of termination.

The Padres refused to announce a decision on Valenzuela, who is 0-2 with a 6.14 earned-run average, but they still have to cut three pitchers by Monday’s deadline and said Valenzuela remains a candidate.

“I had a bad first inning,” Valenzuela said, “but after that, I kept my team in the game. I did my job. The numbers are right there.

“What can I say, it’s not my decision.”

Said Karros: “I’d be surprised if it was do or die. He threw the ball pretty damn good.”

Certainly, it could be a difficult decision for Padre General Manager Randy Smith, who didn’t want him in the first place. Valenzuela was brought onto the team as a gate attraction, but only a paid crowd of 12,860 was reported Wednesday at Jack Murphy Stadium. He has averaged a paid crowd of only 15,065 in three home starts.

“It was a nice experience pitching against him,” said Dodger starter Ramon Martinez (3-1), who gave up seven hits and one run in six innings. “He was one of the best pitchers in baseball. I (wish) him the best.”

San Diego scored its only run in the fifth inning on a two-out RBI double by Eddie Williams. Todd Worrell earned his second save in the ninth with a strikeout and a double-play grounder.