With Zack Greinke back in the fold for the Dodgers, his stint on the disabled list ending a month sooner than expected, someone had to come off the 25-man roster to make room for him.

That someone turned out to be starter Josh Beckett, whose nagging left groin landed him on the disabled list retroactive to Tuesday.

The Dodgers insist Beckett is truly hurt and that he isn't simply being stowed away somewhere trying to collect himself after going 0-5 with a 5.19 ERA this year while pitching into the seventh inning just once over eight starts.

"There's no doubt he's going on the DL for the groin," Dodgers manager Don Mattingly said. "There's no question about that."

Beckett, who's making $15.75 million this year, aggravated the groin Monday against the Washington Nationals.

The Dodgers were hopeful it would dissipate over the next 24 hours. But by Wednesday the groin was still bothering him.

"If he had walked in the next day going, 'I don't really feel this at all. I can go play catch and throw right now.' then you'd have a better indicator," Mattingly said. "But on the second day when he says 'I really don't feel like I can play catch' it's a no-brainer because you know he's not going to be able to make his next start."

The Dodgers hope Beckett can continue some throwing work while the groin mends and anticipate better health leading to better results.

"We want to get him healthy, make sure he's healthy," Mattingly said.

"He's just barely missing. It ain't like he's throwing balls all over the place he's barely missing by two inches when he's trying to hit a corner.

"And I know Josh thinks he has to hit every corner, and can't leave anything over the plate. And he's a control guy. When he's missing there is something going on."

Rookie Matt Magill will start Sunday against the Atlanta Braves in place of Beckett.

Dodgers left-hander Ted Lilly expects to started Wednesday in a rehab game with Single-A Rancho Cucamonga, where reliever Scott Elbert also was scheduled to pitch. Lilly, on the disabled list with a strained right rib cage, said he expected to throw about 75 pitches.