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9/2/2014 7:21 P.M. ET

Reliever Miller day to day after tweaking left leg

BALTIMORE -- Andrew Miller tweaked his left leg on the final pitch of the Orioles' 6-4 loss to the Twins on Monday, and the reliever is considered day to day.

Miller has had issues with his left hamstring in the past, but the O's are hopeful that this was just a cramp, rather than a hamstring issue.

"This one he said was nothing like the [previous] two," manager Buck Showalter said. "We won't use the 'H' word. I'm hoping it was more of a cramping than a hamstring. I'm not going to really address his availability tonight, but we think it's something that should manage itself shortly. Maybe by 9 o'clock."

Miller, who was acquired from the Red Sox at the Trade Deadline, has posted a 1.42 ERA in 13 appearances since joining the Orioles. He gave up only his second earned run on Monday. Including his time in Boston this year, the lefty is 5-5 with a 2.13 ERA and 86 strikeouts.

Miller spent time on the disabled list in both 2012 and '07 with hamstring injuries.

"We've got an idea of what's going on there," Showalter said Tuesday. "He had a little tweak last night on the last pitch. Only time he felt it."

Lower back spasms keep Hardy on the bench

BALTIMORE -- J.J. Hardy was not in the Orioles' starting lineup on Tuesday after exiting Monday's game with lower back spasms, though the shortstop is expected to start on Wednesday.

"I would put it this way: J.J. is an option for us if there's a need he can physically serve," manager Buck Showalter said of Hardy's availability Tuesday. "I expect J.J. to start tomorrow.

Hardy, who missed six games in April with lower back spasms, said he was feeling pretty normal Tuesday afternoon.

"Obviously I want to play, but I think it's probably the smart thing to do," said Hardy. "I felt pretty good the day that I hurt myself in April in Detroit, so just to be safe, take one more day and go from there."

Hardy batted in the top of the seventh Monday, but he did not return for the eighth inning, with Ryan Flaherty taking over at shortstop. Afterward, Hardy said the humidity could have played a factor, telling reporters he can lose up to eight pounds on a hot day, and he smiled Tuesday when asked if he had been hydrating a lot.

"I'm probably about six pounds overweight right now from all the stuff I've been drinking," Hardy said.

The O's, who have lost Matt Wieters and Manny Machado to season-ending surgery, are also currently playing without infielder Steve Pearce.

O's add four to roster; Machado to 60-day DL

BALTIMORE -- As expected, the Orioles added four players to their expanded roster on Tuesday, recalling pitchers Ryan Webb and T.J. McFarland along with catcher Steve Clevenger. The team also selected the contract of outfielder Quintin Berry from Triple-A Norfolk, transferring Manny Machado to the 60-day disabled list to clear a roster spot.

Part of the Opening Day bullpen, the 28-year-old Webb went 3-2 with a 3.80 ERA in 42 appearances for the O's before he was optioned on Aug. 1. McFarland, who has been with the team all year and was briefly optioned on Sunday, has gone 4-2 with a 3.10 ERA in 30 games (one start).

Both McFarland and Clevenger were officially recalled from Class A Aberdeen, with Clevenger also briefly optioned earlier this week to clear a roster spot before the expansion.

The 28-year-old Clevenger has batted .234/.289/.364 in 27 games for the Orioles. He batted .305/.366/.389 with two home runs and 30 RBIs in 64 games for the Tides this season.

This will be Berry's O's debut. The 29-year-old batted .285/.382/.367 with 25 stolen bases in 31 attempts in 112 games for the Tides. Including the playoffs, Berry is 29-for-29 stealing bases in his career at the big league level (Detroit in 2012 and Boston in '13) and adds a speedy element to the Orioles.

Pearce still bothered by abdominal strain

BALTIMORE -- Four days after exiting Friday's win over the Twins with an abdominal injury, Steve Pearce still hasn't swung a bat, and his return for the O's three-game series against the Reds at Oriole Park at Camden Yards is unlikely. At this point, Pearce is looking this weekend's upcoming series vs. the Rays for a possible return.

"I think it'd probably be more realistic that I'll be ready for Tampa," Pearce said, "because right now, I'm shut down for everything."

Pearce left before the fourth inning against Minnesota with a right abdominal strain, with an MRI confirming the injury the following morning. He has been shut down from all baseball activities since the injury, relegated to just playing catch in order to keep his arm strong.

Pearce said he only feels pain in his abdomen when he swings a bat, which he hasn't done since sustaining the injury. So he's been totally pain-free for the past few days.

"It's funny, I feel like maybe I should take some swings to see if I still feel it, so I'm really kind of confused on how all this works," Pearce said. "But I'm confident that they know what they're talking about. I'd rather get this thing behind me, instead of have symptoms in a couple weeks."

Manager Buck Showalter said on Monday that he expected Pearce to have a "test run" during this series against Cincinnati, and he still isn't ruling out some playing time for his surprising slugger. Starting, though, is still a little a bit further away.

"There's some things I want him to get through before he does that," Showalter said, "but we could use him if we had to."

Pearce is in the midst of a breakout season, with career highs of 16 home runs and a .289 batting average entering Tuesday. He had become Baltimore's everyday first baseman when Manny Machado's season-ending injury forced Chris Davis to slide over to third. Before that, he received regular playing time in left field and at first base.

In Pearce's absence, Davis has moved back to first and Jimmy Paredes has gotten the majority of the starts across the diamond. The O's took three of four from the Twins without Pearce, and with an 8 1/2-game lead in the American League East, the Orioles can afford to be cautious with Pearce.

"This is the hardest thing ever," Pearce said. "Being here watching the guys, not being able to work out, hit and doing all that stuff is kind of hard for me to sit back -- especially since I don't have any pain and I feel like I can do it. But they just want me to really let this thing calm down."

Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Facebook and Twitter @britt_ghiroli. David Wilson is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.