BALTIMORE -- Left fielder Endy Chavez was out of the lineup on Wednesday after straining his right hamstring in the sixth inning of Tuesday's win over the Pirates, and the Orioles are taking a wait-and-see approach to determine how the injury responds before making a move.

"He's a little sore today, but we'll probably make a decision [on Thursday] about what we want to do there," manager Buck Showalter said. "It will be kind of tough going into six National League games with a short bench. It's kind of tough to test it out, because you don't want to injure it further."

Chavez injured the hamstring while advancing to second on an errant throw by Pirates reliever Chris Resop after hitting a single in the sixth inning. Chavez was on the disabled list earlier this season with an injured left oblique and is hitting .171 with four RBIs in 32 games.

"It's tough when you're trying to help the team and play every day," Chavez said. "Now this happens. It's a little frustrating."

Matusz scratched; Arrieta starts against Bucs

BALTIMORE -- Brian Matusz said he felt fine, but manager Buck Showalter wasn't taking any chances, bumping Matusz's Wednesday start against the Pirates to Friday vs. the Braves while the left-hander recovers from a contusion to his nose, an injury he sustained while practicing his bunting.

Starting in Matusz's place against Pittsburgh was righty Jake Arrieta, who had been moved to the bullpen after struggling to a 2-8 mark and 6.32 ERA in 13 starts.

"We're fortunate to have someone rested," Showalter said of Arrieta, who last pitched on Friday against Philadelphia. "If [Matusz] had a problem in the first or second inning, we'd have to use a lot of bullpen -- which could happen with anybody pitching, for other reasons. We're fortunate to be able to give him a couple more days. So he'll fly out of here [on Thursday] afternoon and hopefully beat us to Atlanta and pitch the first game."

While Matusz was bunting on Tuesday in preparation for Baltimore's upcoming Interleague road trip to two National League parks, a ball came up and struck him in the nose, causing plenty of bleeding and swelling; X-rays came up negative.

Matusz said that he was ready to pitch on Wednesday, but Showalter informed him that he would be pushed back. Tommy Hunter (2-3, 5.40 ERA) will pitch the series finale against Pittsburgh on Thursday.

"I should be fine for Friday," Matusz said. "There's a little bit of pain there, but I've been doing activities, and I feel fine. I can breathe just fine. I slept really well last night, and I feel 100 percent."

Stepping in on short notice was Arrieta, who allowed nine runs on 11 hits in four innings his last time out and has dropped six straight decisions since a May 2 victory over the Yankees.

Showalter said that turning to Arrieta was the team's best option given the circumstances.

"Out of all the things we had options to do, it probably fit the best," Showalter said. "We'll see what Jake does tonight. I'm curious to see how he pitches."

Roberts receives congratulations on comeback

BALTIMORE -- After making his triumphant return from a concussion on Tuesday night, going 3-for-4 with an RBI, second baseman Brian Roberts got a shaving cream pie in the face from Adam Jones and dozens of congratulatory messages and texts from friends and former teammates.

"I've spent half the day trying to get back to everyone," a smiling Roberts said. "I had so many people that have been part of this process with me, and they've all had a lot of great things to say."

Ex-Orioles Jay Gibbons and David Segui were among those who reached out.

"There were a lot of people in the baseball community," Roberts said. "I'm very appreciative."

Worth noting

• Major League Baseball and the Orioles announced on Wednesday that the start time for the game on Saturday, July 14, against the Tigers has been moved from 7:05 p.m. ET to 4:05 p.m. after being selected for broadcast by FOX.

That date is also the unveiling of the Jim Palmer sculpture, which will take place at 2:15 p.m.