Ankiel was hospitalized for observation after he crashed into the wall while chasing a fly ball hit by Pedro Feliz in the top of the eighth inning in a 6-1 St. Louis loss to Philadelphia Monday.
Ankiel caught the ball on the dead run and, after his face struck the padding on the wall, he fell to the ground. He was strapped with a precautionary neck brace, carted off the field and taken to Missouri Baptist Hospital.
Tests were negative, but team officials said Ankiel will continue to recover on the DL.
"I just think that by the time he's going to feel well enough to practice and get himself back in shape, days will have passed," Manager Tony La Russa said on the team's Web site.
Ankiel is batting .247 with two home runs and 11 RBI in 24 games this season.