PAWTUCKET — The Pawtucket Red Sox are a beat-up unit right now and they played like one in yesterday’s 7-3 loss to the Buffalo Bisons.

The Sox lost for the second straight game and fourth time in the last six outings. The team’s offense, a season-long trouble spot, is reeling right now with leadoff sparkplug Jacoby Ellsbury nursing a groin injury and the team’s most consistent hitter, David Murphy, traded to Texas.

Under a blazing, 92-degree sun at McCoy Stadium yesterday, the PawSox managed just seven hits for their three runs. Starting pitcher David Pauley held Buffalo in check for six innings but reliever Edgar Martinez gave up a two-run home run to Yamid Haad in the eighth inning and a throwing error by catcher George Kottaras helped Buffalo head out of town with a sweep of the brief, two-game series.

“We just don’t have any offense right now,” said manager Ron Johnson. “We’re not getting that ball to the gap that all teams need. We’re asking our pitching staff to do an awful lot every game to keep us in it.”

Without Ellsbury and Murphy, “we’re a different ball club right now,” Johnson said. But he quickly said that’s no excuse for his team either. Pawtucket is second to last in the International League with a .253 team batting average and no one is hitting over .300. To fill out the roster, the Sox promoted outfielder Matt Sheely, infielder Aaron Reza and pitcher John Barnes from Single A. Sheely started yesterday, while the knuckleballing Barnes will start in a doubleheader against Rochester (6 o’clock) tonight.

“When players come and go, it opens up possibilities for other guys. You have to take advantage,” Johnson said. “This is the time, August now, when everybody is going to remember you by. This is go time.”

Buffalo scratched out a single run off Pauley in the third inning but the Sox answered with two runs in the third and one in the fourth. Both runs in the third came on balls that didn’t pass the pitcher’s mound. With Ed Rogers at second base, Sheely bunted safely up the third-base line. A wild throw to first sailed into right field, allowing Rogers to score. Sheely went to second on the error and moved to third on a fly out. Jeff Bailey then chopped a ball in front of the plate that died to the right of pitcher John Koronka for a hit. Pawtucket built its lead to 3-1 in the fourth when Rogers singled in Alex Prieto.

A solo home run by Jon Van Every in the fifth cut the lead to 3-2 but Pauley and Lincoln Holdzkom escaped a bases-loaded, one- out jam in the sixth with only one run coming home.

While Buffalo’s relievers easily handled the Sox over the last three innings, Martinez gave up the go-ahead runs in the eighth and two more in the ninth. Haad lined his two-run blast onto the berm in left in the eighth. With two outs in the ninth, Buffalo’s Ben Francisco doubled to left. Ryan Mulhern followed with a sharp single to left that scored Francisco. Kottaras caught the throw from Bobby Scales but threw the ball into a vacant center field trying to cut Mulhern down at second. Mulhern came all the way around on the error to boost the lead to 7-3.

PAWSOX PATTER: Murphy was traded to Texas Tuesday in the package for Eric Gagne but was still at McCoy yesterday. Murphy’s wife, Andrea, is due to have the couple’s first child this weekend in Boston. Texas’ Triple-A team, Oklahoma City, is playing in Fresno, Calif., so the Rangers decided Murphy could join the team after the baby is born. Murphy is a Texas native so moving home couldn’t come at a better time.

“It’s definitely bittersweet,” he said. “I’ve made a lot of great friends here, but Texas is home for me and this may work out for me in the big leagues if things break the right way.”

kmcnamar@projo.com