La Russa also announced that infielder Khalil Greene would not be on the roster after the Cardinals decided to go with 12 pitchers and 13 position players on the 25-man squad.
"I just think that he is at the point where, and I told him this, we're feeling great that he feels good, and I think he's excited about his prospects for next year," La Russa said of Greene. "But as far as his playing time, I think Troy will give us more."
The Cardinals held an optional workout at Busch Stadium on Monday afternoon before boarding an early-evening flight to Los Angeles. They will work out again Tuesday afternoon at Dodger Stadium before opening the series Wednesday night.
Glaus, who hit .270 with 27 home runs and 99 RBIs for the Cardinals in 2008, missed the first five months of the season as he recovered from shoulder surgery. He was activated from the disabled list on Sept. 1 but suffered from back spasms and a tweaked oblique soon after he rejoined the club.
The slugger will enter the playoffs having participated in just 15 games and with only 29 at-bats. Glaus is hitting .172 (5-for-29) with two doubles and two RBIs and has eight strikeouts in mostly pinch-hitting duty -- likely what his role will be in the postseason.
Greene, who becomes a free agent at the end of the season, suffered from social anxiety disorder. He hit .200 in 170 at-bats during the regular season.
The decision to go with 12 pitchers means that two of the four among Blake Hawksworth, Mitchell Boggs, Todd Wellemeyer and Brad Thompson will be on the playoff roster. Hawksworth and Boggs, both rookies, are the likely choices to make the cut based on their performances and the number of their appearances down the stretch in relation to Wellemeyer and Thompson.
"We haven't decided that yet," La Russa said. "But we're going to take 12 pitchers.
"The experience of a Thompson and a Wellemeyer. You look at Boggs, Hawksworth, [Kyle] McClellan, [Jason] Motte -- they are all first timers. We're thinking through all of that stuff. I think its one of those deals where when you have it figured, you might as well announce it. "
La Russa again declined to announce a fourth starter but downplayed any chance that Game 1 starter Chris Carpenter could come back on three days' rest if they are trailing in the series.
"We're going to play Wednesday and Thursday, and do what we can to win, and use everybody that we have to, and then assess where we are when we fly back Friday," La Russa said. "But its going to be Lohse or Smoltz."
B.J. Rains is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.