Ankiel has worked out with the team the last three days, but manager Tony La Russa said Friday that the center fielder didn't appear close to coming back. Ankiel has a bruised right shoulder and overall soreness from a headfirst crash into the wall after running down a fly ball at the warning track earlier this month.
La Russa said Ankiel "still felt something" when he was eligible to come off the DL on Wednesday.
"It probably comes down to when the discomfort is gone," La Russa said. "I really have no idea. He wants to get back and stay back and I don't blame him."
Ludwick is eligible to return from a right hamstring injury next Friday and the Cardinals expect him to be ready immediately.
La Russa said Ankiel wasn't yet begun working out vigorously and may require a rehab assignment. The manager said Ludwick is a better bet to return without a rehab because he has more experience as a position player.
Catcher Yadier Molina was not in the lineup for Friday night's opener of a three-game interleague series against the Royals, ending a run of 12 consecutive starts, with backup Jason LaRue getting the call.
Molina, in a 3-for-27 slump, has been taken out of some recent lopsided games but played every inning in a three-game sweep of the Cubs ending Thursday.