Boston ? Woody Williams is a constant in a St. Louis Cardinals rotation that manager Tony La Russa keeps juggling. The right-hander will make his third straight series-opening start in Game 1 of the World Series tonight.

La Russa said he was considering using 15-game winner Matt Morris on three days’ rest in Game 2 on Sunday because Morris had coped with the postseason better than the other choice, Jason Marquis. Plus, Morris is relatively fresh because he was lifted after five innings of Game 6 of the NLCS on Wednesday.

Marquis struggled the last month of the season, going 1-3 with a 5.33 earned-run average, and has struggled in both of his playoff starts, allowing six runs in seven innings.

La Russa said Jeff Suppan, a 16-game winner, would go in Game 3 and could also pitch in Game 7, just as he did in the NLCS. The Cardinals have been impressed with Suppan’s poise under pressure.

“The only thing we’re saying is it’s pretty tough not to pitch Suppan in Game 3,” La Russa said.

In the NLCS, La Russa went with a rotation of Williams, Morris, Suppan and Marquis, in that order. In the division series against Los Angeles it was Williams, Marquis, Morris and Suppan.

One pitcher who won’t be in the mix is Chris Carpenter, who has been out since Sept. 18 because of nerve damage in his right biceps.

Carpenter, a 15-game winner who would have been the team’s No. 1 postseason starter, has thrown two bullpen sessions without mishap, but the team believes the risk is too great.

“It’ll be the same four guys,” La Russa said Friday at Fenway Park. “I was so concerned with beating the Astros that I didn’t really start messing around with it until early this morning.

“It’s a little tricky, so that’s why it’s not easy to announce it.”

Williams trailed the rotation with 11 victories, but the Cardinals won 16 of his last 19 starts. He would pitch again on regular rest in Game 5.

Williams has been effective in his three postseason starts this year, with a 2-0 record and 2.84 ERA. He allowed one hit in seven innings and didn’t let a base-runner past second in Game 5 of the NLCS.

He did that despite straining a calf muscle running to first base while batting in the top of the third.

“As a kid growing up, this is what you play in your backyard and you pretend for, this situation,” Williams said. “And here it is, a dream come true.

“I’m very fortunate to have this honor and for my team to have the confidence in me the way they do.”

Morris was much better at home (9-4, 3.69 ERA) than on the road this year (6-6, 6.02). But he’s much more experienced in the postseason, making eight starts.

The biggest problem with Morris has been his inconsistency.

The opening-day starter for the third straight season, Morris was 15-10, but his 4.72 ERA trailed the rotation, and he had a tendency to follow some of his best outings with some of his worst.