SAN DIEGO -- The promise of another October informs nearly every decision Larry Walker makes these days. Walker has battled a herniated disc in his neck nearly all season, but he continues to try anything and everything to ensure that he can play in the postseason.

Walker was placed on the 15-day disabled list on Tuesday, retroactive to Saturday, after undergoing a third cortisone injection in his neck. The thought is that by giving him a lengthy rest, perhaps the injection's beneficial effects will last longer once he returns.

"I've got 12 days [until I return], because it's retroactive," Walker said on Tuesday. "So 12 days from now, we'll see where it stands. If I need a few days more, then I'm sure we'll do that. If not, we'll go get 'em. Two weeks from now, I can't say where I'm going to be.

"But after getting the other shots and then playing two days later, probably tomorrow I could play, in reality. But we're trying to fix it up so that if I have to take another shot, it's just going to be one more. It's not going to be more than that."

Walker, in conjunction with the team's training and medical staff, hopes to minimize the number of additional injections the outfielder will undergo. It's not a pleasant experience, taking a needle into the neck, but Walker is willing to put up with it in hopes of playing in the World Series for a second consecutive season.

"It's worth being the champions," he said. "We have a chance to win. Not a lot of ballclubs get to be in the situation we're in. It's been a long time coming to be on a team like last year and this year, in my career. I've been on a couple of good teams, but nothing like this."

It's uncertain whether Walker will return at the end of 15 days -- neither he nor manager Tony La Russa nor head athletic trainer Barry Weinberg was comfortable making a pronouncement. Walker will not participate in any baseball-related activities for a couple of days, and it may be several days before he swings a bat.

John Gall was called up to take Walker's spot on the roster. St. Louis has four of its eight Opening Day position players on the disabled list.

"It's nice to have to plug in a guy or two here and there, but we're plugging in a lot of guys," said La Russa. "But the reality is the same: The games count, and it's an opportunity for a lot of guys. I think we'll have a frame of mind to go out there and compete, and we'll find a way to get through it."

Rodriguez cleared to play: John Rodriguez was approved to play by the Cardinals' medical staff, but La Russa elected to hold him out one more day as he recuperates from a sprained ankle. Gall and So Taguchi were tapped to start in left and right field, respectively.

That's two right-handed hitters in place of two left-handed hitters against the right-handed Woody Williams, which likely is not a coincidence. Williams, who relies heavily on a cut fastball, has inspired a significant reverse platoon split this year and last year -- right-handers hit him quite a bit better than lefties.

Today in Busch Stadium history: On July 26, 1973, the Cardinals swept a doubleheader from the Mets, 13-1 and 2-1. The second game was a thriller, with Alan Foster outdueling Jerry Koosman, but the real highlights for the home fans came in the twinbill opener. In that game, Bob Gibson dominated like few players could. The Hall of Famer-to-be pitched a complete game, allowing only an unearned run on six hits. He also was brilliant at the plate, with two hits and five RBIs, including a grand slam. Thanks to Project Retrosheet (www.retrosheet.org) for the information.

Baby 'Birds: Anthony Reyes was the hard-luck loser for Triple-A Memphis against Round Rock on Monday. Reyes allowed a run on five hits with five strikeouts and one walk over five innings, but took the defeat as Memphis fell, 4-1. Pete Zocolillo had three hits, including two doubles. ... Chris Lambert turned in a strong game and his offense went nuts as Double-A Springfield beat Arkansas, 13-7, on Monday. Lambert pitched six innings, allowing a run on seven hits, striking out five and walking two. After a rough start in Double-A, Lambert has come on strong -- in his last six starts, Lambert has a 2.57 ERA with 35 Ks and 16 walks in 35 innings.

Class A Palm Beach swept a doubleheader against Sarasota, 3-2 and 4-2 on Monday. Eric Haberer pitched a seven-inning complete game in the nightcap. ... Class A Quad Cities lost, 5-4, to Southwest Michigan in 10 innings. Nick Stavinoha cranked out two more hits to get his average to .347. ... Short-season New Jersey capitalized on three errors and a wild pitch to beat Lowell, 5-3, on Monday. Tyler Greene doubled, walked and scored two runs. ... Rookie-level Johnson City was pummeled by Greeneville, 17-5, on Monday. Daryl Jones went 2-for-5.

The player of the day is Springfield third baseman Travis Hanson, who had the biggest of a number of big offensive days in the win over Arkansas. Hanson went 3-for-5 with two home runs and a double, drove in four runs and scored three. Hanson, 24, was the Cardinals' ninth-round pick in the 2002 First-Year Player Draft.

Coming up: Game 2 of the three-game series at PETCO Park has another 9:05 p.m. CT start on Wednesday. It will be Jason Marquis going for the Cards, looking again for win No. 10, while Jake Peavy is the Padres' Wednesday starter.