Houston Astros left-hander Andy Pettitte said he will be at full strength Monday night, when he has the chance to pitch his hometown team into its first World Series. And no, he won't be running the bases during batting practice.

"I'm definitely good to go," Pettitte said Sunday before the Astros beat the St. Louis Cardinals to take a three-games-to-one lead in the National League Championship Series.

In the hours before his start in Game 1 on Wednesday in St. Louis, Pettitte was struck in the back of his right knee by a ball off the bat of fellow Houston starter Roy Oswalt. He still made his start, but the injury required treatment and limited his effectiveness. Pettitte gave up five runs in six innings, but refused to blame the poor outing on his knee.

"I was just bad," he said. "I threw a lot of balls right in the heart of the zone."

Since that start, though, Pettitte said his routine has been unaffected by the injury.

"He's thrown in the bullpen and he's a whole lot better," Astros Manager Phil Garner said. "I feel 100 percent confident that he will be 100 percent tomorrow, if we can keep him from getting hit with anything between now and then."

When he takes the mound at Minute Maid Park, Pettitte will make his 33rd postseason start, breaking a tie with Tom Glavine for the most all time. He is 14-9 with a 4.15 ERA in the playoffs over his 11-year career. He has never been on a team that did not advance to the postseason.

Cardinals' Nunez Hurt

Cardinals third baseman Abraham Nunez, injured in a collision with Houston's Jason Lane in Game 3 on Saturday, was replaced in the starting lineup by veteran John Mabry. Nunez suffered a deep bruise above his left knee when Lane slid into it in the sixth inning of Game 3.

"We're deep enough to cover," Cardinals Manager Tony La Russa said.

Mabry had only four at-bats in the playoffs prior to Sunday, when he went 0 for 4 and grounded into the game-ending double play. Normally a reserve outfielder, he started 12 games at third base during the season, making one error. The first ball of the game was hit directly at him by Houston leadoff man Craig Biggio, and he fielded it cleanly.

La Russa said he didn't know if Nunez would be able to play in Game 5 Monday night. . . . A day after sitting out with neck pain and a lower back sprain suffered in an awkward fall in Game 2, Cardinals left fielder Reggie Sanders returned to the lineup but was ineffective, going 0 for 4 with two strikeouts, including one with a man on second in the fourth inning.