Adam LaRoche placed on 15-day disabled list

MILWAUKEE - Giving him time to rest his left shoulder after he played the first 43 games with a torn labrum in his left shoulder, the Nationals put first baseman Adam LaRoche on the 15-day disabled list today, retroactive to Sunday. They will add a player to their roster to take LaRoche’s spot tomorrow.

The first baseman had played through the injury all season after doctors told him it would mostly affect his ability to throw. But he’s hitting .172 with three homers in 43 games. His shoulder might not be the reason for his slow start, especially since LaRoche has historically hit poorly the first two months of the season, but the Nationals will give him time to rest in hopes it helps the problem.

“We’re going to just not have any baseball activities for a while and see if that helps the shoulder calm down,” manager Jim Riggleman said.

The Nationals will start Michael Morse at first base tonight, though Riggleman wouldn’t commit to any long-term plans. But if LaRoche is out for a couple weeks, it’s likely he’d have to go on a rehab assignment after he starts working again. That means the Nationals could be without the first baseman until at least mid-June.

At this point, it’s unclear if they’d lose him longer than that. LaRoche will likely need surgery to repair his left shoulder at some point, but the Nationals will wait to see if he gets back to a point where he can play with the injury the rest of the season.

“Adam is basically saying, ‘It doesn’t hurt, but I can’t believe I’m missing these pitches, so maybe it’s something there not allowing me to get to the ball,’ ” Riggleman said. “You’ve got to explore that, to see if no throwing activities, no lifting, no swinging will let it calm down to the point that maybe then it can go back up. It’s just unfortunate that he’s got to go through this, but this is the step we’re taking now.”

Without LaRoche, the Nationals will have to cobble together a plan at first base for at least the next several weeks. They’ll particularly miss him on defense; LaRoche hasn’t made an error at first, and has saved a handful of errors by scooping throws out of the dirt.

Morse can play there, and Riggleman said Rick Ankiel - who could return to the roster this week after starting a rehab assignment at Double-A Harrisburg tonight - would also take some ground balls at first base. Chris Marrero, the team’s top pick in the 2006 draft, is at Triple-A Syracuse, though it’s likely the team would want him to get some more seasoning there before bringing him to the majors.

But as much as LaRoche has hit below his standards, his loss will hurt the Nationals on defense.

“Adam’s a great defensive player, a big bat in the lineup,” Morse said. “I hope for him to come back soon.”