BALTIMORE -- Vladimir Guerrero was out of the lineup on Thursday due to lingering soreness in his right hand, where he was hit Sunday by Red Sox pitcher Kyle Weiland. Guerrero, who normally hits in the cleanup spot as the Orioles' designated hitter, was replaced in both roles by Matt Wieters.

Manager Buck Showalter said Guerrero told him his wrist had been improving, but he wanted to take another day to see how it feels. The Orioles may call for an X-ray after consulting with team physician William Goldliner.

Third baseman Mark Reynolds, who was also forced to leave the game Sunday after being hit in the right hand by Weiland, started Thursday's series opener with the Indians.

The initial X-rays, taken on Sunday, of both Reynolds and Guerrero came back negative.

Guerrero hit .279 with seven home runs and 31 RBIs in the first half of the season. Four of those homers came in April, and the former Silver Slugger winner has three RBIs in his past 10 games.

Roberts given go-ahead to increase workload

BALTIMORE -- Brian Roberts, dealing with concussion-like symptoms, is improving and was told by concussion specialist Michael Collins on Thursday that he can increase his workload in Sarasota, Fla.

The Orioles' second baseman was not given a timetable for his return, and he is still not allowed to resume full baseball activities.

The sign of improvement is some of the only positive news Roberts has received since sustaining the injury while sliding headfirst into first base on May 16 at Fenway Park. He was cleared to begin a plan of light upper-body exercise by Collins on June 21.

This is the second time in as many seasons that Roberts has been bothered with a long-term injury; he missed 59 games in 2010 with a herniated disk in his lower back. The 33-year-old infielder also battled back and neck injuries this Spring Training after another headfirst slide into first base.

Scott scheduled for cortisone injection

BALTIMORE -- Orioles outfielder Luke Scott, who is eligible to come off the 15-day disabled list on Tuesday, will get a cortisone injection in his right shoulder Friday and does not know if he will be able to return against Boston.

Scott has been battling a torn labrum in his right shoulder all season and said he will only be able to test it following the shot. For now, he is just resting, eager to start his rehab assignment.

"Everything happens in stages, and we're not finished the stage that we're in," Scott said.

Manager Buck Showlater said Scott would likely need to have some at-bats with a Minor League affiliate before being activated by Baltimore.

"Luke actually hasn't done anything, which is what we were hoping he would do with the weight room and everything else," Showalter said. "He hasn't picked up a bat or done anything. I'm hoping Saturday or Sunday he's able to go out and get some at-bats."

The Baltimore slugger, who is hitting .223 with nine home runs this season, also sustained a knee contusion on June 28 after making a leaping catch at the wall against the Cardinals.

Arrieta, Simon, Atkins given weekend starts

BALTIMORE -- With a banged up starting rotation, the Orioles will have Jake Arrieta throw Friday, Alfredo Simon on Saturday and Mitch Atkins start Sunday in the series finale against the Indians. Baltimore is still undecided on who will get the nod Monday against Boston.

Simon will leave the team Sunday to tend to legal matters in the Dominican Republic, but he is expected to be back on Monday or Tuesday.

Three Orioles pitchers who were once in the starting rotation are now in the Minors. Zach Britton is in Double-A Bowie, while Brian Matusz and Chris Tillman are pitching for Triple-A Norfolk. Britton will pitch three innings Friday and make another appearance on July 20.

In their place, Baltimore has called up Atkins, used Chris Jakubauskas in a spot-starter role and converted Simon from a reliever. However, these replacements have not alleviated the Orioles' rotation troubles, putting up high run totals in short starts.

Tidbits

• Cesar Izturis (elbow surgery) could begin games in the Gulf Coast League on Wednesday, play a stint for Double-A Bowie and be activated on July 23 in a best-case scenario.

• Brian Roberts' Baseball Bash has been rescheduled for Aug. 28.

• The Orioels will hold their 25th annual Food Drive at Camden Yards on Friday, Saturday and Sunday, accepting donations from fans from the time the gates open until the second inning.