Ellis was slowed by right patella tendinitis earlier this month and said he re-aggravated his knee when he slipped on a soggy field during a March 25 game. Ellis played in the Cardinals' Grapefruit League game the next day but has been limited since. Though he was on the field for Sunday's workout at Great American Ball Park, Ellis did not participate in ground-ball drills with the other infielders.
"I'm disappointed," Ellis said. "I felt like this was the best thing for the long haul of the season. If you have to miss time, miss it now and be ready for the rest of the season."
The Cardinals can backdate Ellis' DL stint to March 27, which makes him eligible to come off as early as April 11. In the meantime, Kozma will remain on the big league roster as a backup infielder.
"It's just something that's got to heal and get better for me to be as effective on the field as I can be to help the team win games," Ellis said. "It's one thing to go out there and play hurt, but to help the team win ballgames, it needs to get a little bit better."
Ellis is one of three players who will begin the season on the Cardinals' 15-day DL: Jason Motte continues his rehab from Tommy John surgery, and Jaime Garcia is on a delayed throwing program after dealing with bursitis in his left shoulder early in Spring Training.
Here is a rundown of the Cardinals' official roster:
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.