CHICAGO -- The Pirates are hopeful that Bobby Crosby will be cleared to play in the next day or two, but for now, Pittsburgh will play without two second basemen.

Crosby and Neil Walker, neither of whom is on the disabled list, remain sidelined after eerily similar collisions with Pittsburgh's right fielder. The absence of the pair forced the Bucs to play with just three hitters -- Ryan Church, Delwyn Young and Jason Jaramillo -- on the bench on Tuesday.

Crosby certainly looks poised to return before Walker. After colliding with Lastings Milledge in Monday's win over the Cubs and leaving the game an inning later, Crosby said he expected to participate in some pregame activities on Tuesday. Still, for precautionary reasons, he wasn't available for the game.

"I have a little bit of a headache, but other than that, I'm fine," Crosby said.

Manager John Russell said there is a chance that Crosby will be cleared to return to the field for Wednesday's series finale with the Cubs, though Thursday looks like a better option.

Walker, who suffered a concussion on Friday, visited a specialist in Pittsburgh on Tuesday. Russell said that he had received word that Walker was continuing to feel better, though the concussion symptoms haven't yet completely subsided. Those symptoms will have to disappear before Walker will be allowed to participate in baseball activities again.

If those symptoms are still bothering Walker at the end of the week, the Pirates will revisit the possibility of a DL stint. For now, the hope is that Walker can avoid that altogether.

"He felt much better today, so I'm hoping in the next day or two, he's going to feel good and we can get him back to activity," Russell said. "Each day, the symptoms are getting better."

Pirates give LaRoche shot at second base

CHICAGO -- After weeks of heavy tutorial and extra work, Andy LaRoche made his Pirates debut at second base on Tuesday.

LaRoche has been putting in hours of defensive work at second with infield coach Carlos Garcia for about three weeks now, after he lost his starting job at third with Pedro Alvarez's arrival. And with Neil Walker and Bobby Crosby unavailable on Tuesday because of injuries, manager John Russell felt comfortable enough giving LaRoche his first in-game test at the new position.

"Is he 100 percent ready? He's close," Russell said, suggesting the shortage of infielders pushed up LaRoche's timetable. "He's worked awfully hard. Being on the road for nine days, you can't do as much work. But he's done pretty well. He's got instincts of being an infielder, and I think that will take over. He should be fine."

Russell's other option at second would have been Delwyn Young, though Russell preferred having LaRoche in the lineup against a left-handed starter. Southpaw Ted Lilly got the call for the Cubs on Tuesday.

LaRoche started two games at second with the Dodgers in 2008, and played another eight there in the Minors. The majority of his defensive experience at the position actually came in high school when he was an everyday second baseman.

"I'm excited," LaRoche said of the start. "I've been working a lot out there, whether it's early or whether it's during batting practice. I'm starting to feel comfortable over there turning two, getting my flips to second and ground balls."

His biggest concern? Remembering where to be for cutoffs and relay throws.

"Hopefully we'll get a little refresher course before the game," he said smiling.

Simply being in the starting lineup is a big deal for LaRoche, who had just nine at-bats since June 16. He'd made only one start during that span, and had gone 1-for-6 off the bench.

"It feels weird over there [on the bench]," LaRoche said. "You kind of get bored. It has been tough. But you've got to stay ready, and whatever they want you to do, you've just got to be ready for the opportunity and take advantage of it when it comes."

Worth noting

Outfielder Ryan Church remains available to hit, but the outfielder is still dealing with an inner right thigh bruise from Friday's collision with Neil Walker. Church said the discomfort has spread up his leg and still bothers him when he runs. ... Five players from the Pirates' Double-A Altoona affiliate have been chosen to participate in the Eastern League All-Star Game on July 14. The group includes catcher Hector Gimenez, first baseman Matt Hague, infielder Josh Harrison, right-hander Derek Hankins and left-hander Rudy Owens. The last time Altoona had five players named to the All-Star Game was in 2007. ... Catcher Tony Sanchez has been replaced on the All-Star Futures roster by catcher Hank Conger (Angels). Sanchez is unable to participate after having jaw surgery last week. ... Infielder Ramon Vazquez, whom the Pirates released just before the start of the season, has signed a Minor League contract with the Astros. Pittsburgh is still on the hook for Vazquez's $2 million salary, though Houston would pay a prorated portion of the Major League minimum ($400,000) if Vazquez is called up later this season.