Holliday, who had an appendectomy on Friday, might be in a position to return to the lineup this weekend when the Cardinals take on the San Francisco Giants.
"He is not being disabled. He's making enough progresss now that he'll be back before 15 days," La Russa said Tuesday, according to the St. Louis Post-Dispatch. "So we'll keep it going, without adding anyone [to the roster]."
The Cardinals will play a man short for the fourth straight game Tuesday night against Pittsburgh.
Holliday, the Cardinals' cleanup hitter, likely will return to the lineup at some point during the Cardinals' 10-game trip to San Francisco, Arizona and Los Angeles, which begins Friday. He expects to travel with the team.
On Monday, Holliday said he was feeling better each day. He played catch and ran sprints Tuesday and expects to take batting practice on Wednesday.
The team has discussed the possibility of him pinch-hitting before he resumes play in the field.
Information from The Associated Press was used in this report.