PAWTUCKET, R.I. — Like any major league team, the Boston Red Sox are looking for more thump in their lineup.

David Ortiz has carried the load with a team-leading 30 home runs. But he is 38.

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Red Sox designated hitter David Ortiz has 30 home runs this season, but he is 38. Who will be Boston's next power hitter? The Associated Press

Boston traded for Yoenis Cespedes, who has 21 home runs. He has one year left on his contract.

Mike Napoli was supposed to protect Ortiz. He hit 23 home runs last year but has just 15 this season. He also has one more year remaining on his contract.

Boston announced Saturday that it signed coveted Cuban free agent Rusney Castillo to a seven-year deal. His game is reportedly more speed than power.

So where can the Red Sox find more thump? How about in their own backyard?

Maybe you haven’t noticed, but Bryce Brentz returned this month to Triple-A Pawtucket. He came off the disabled list Aug. 2 and hit .291 with four home runs in his first 12 games.

In 137 Triple-A games overall, he has 27 home runs.

So why isn’t Brentz in Boston, getting a taste of the big leagues as the Red Sox look to 2015?

Because those 137 Triple-A games have been played over two seasons.

Since Brentz hit 17 home runs for the Portland Sea Dogs in 2012 and was invited to major league spring training camp the next year, he hasn’t been able to stay healthy.

Before the 2013 camp began, Brentz accidentally shot himself in the left leg while cleaning his gun. His injury was not serious, but he missed major league camp.

Brentz began last year in Pawtucket and hit 17 home runs in 82 games, but he injured his right knee while sliding on July 5 and had season-ending surgery on July 16.

This year, Brentz injured his right hamstring in May. Initially thought to be a day-to-day problem, the injury only worsened and Brentz was sent to Florida for extended rehab.

“I hate that the last two years I’ve been injury-prone. I’ve never really had that label,” Brentz said. “Hopefully that’s the end of it.”

But the way Brentz has jumped back into his power- swinging ways brings hope.

“We’ve seen the impact, like he’s shown in the past – impact to all fields,” said Pawtucket Manager Kevin Boles, who also managed Brentz in Portland in 2012.

Impact. Another word for thump.

Homegrown power is a rarity. Boston is hoping it has that with Will Middlebrooks and, to a lesser extent, Xander Bogaerts.

Middlebrooks, 25, broke out in 2012 with a 75-game burst of 15 home runs and a .288 average. But then came injuries and struggles, and Middlebrooks has not been the same. He did hit 17 home runs (with a .227 average) in 94 games last year, but is hitting .187 with two home runs in 35 games this season.

Bogaerts opened eyes as an 18-year-old prospect in low Class A Greenville in 2011, hitting 16 home runs in 72 games. Still only 21, Bogaerts’ power may come in the majors (he has eight homers this year), but the bigger concern is his overall hitting (.223 average).

That brings us back to Brentz. A supplemental draft pick (36th overall) in 2010, Brentz has a track record of power. Now it’s a matter of staying healthy.

“I just think it’s him gaining confidence that he can hold up, and also the confidence with the timing,” Boles said. “He’s an impact bat … This will slowly, gradually come together.”

Maybe Brentz will get a September call-up to the majors; if anything, he could use the extra at-bats.

He is on the 40-man roster for the first time (and therefore will have minor league options for two more seasons), so there is no reason to rush.

No reason except for the fact that Brentz has power, the kind that Boston could use.

ALEX HASSAN is an outfielder likely to get a September call-up (along with recently demoted Jackie Bradley Jr.). Hassan, 26, has been an interesting case since his breakout year in Portland in 2011 (.291 average, .860 OPS).

Plagued by injuries the past two seasons, Hassan was off to a slow start this year in Pawtucket (.217, .621) when the Red Sox unexpectedly called him to Boston for two games in early June.

Since then, Hassan is batting .326 in Pawtucket. His OPS is now .802. That call-up to Boston did wonders.

“It took the question away whether I would ever get there,” Hassan said. “I guess it helped my confidence. I’m playing how I expected to play.”

TRAVIS SHAW tried too hard to hit with power last year in Portland and ended up slumping to a .221 average with 16 homers.

Shaw, 24, a first baseman, returned to the approach that first made him successful. He hit .305 with 11 home runs in 47 games in Portland and has moved on to Pawtucket. His average has dropped to .271, but he has 10 home runs. His 21 home runs overall are second only to Ortiz in the Red Sox organization.

“This year’s been night and day from last year,” Shaw said. “I’ve been pretty consistent; not a lot of valleys. Just trying to finish strong.”

An invitee to major league spring training in 2014, Shaw is a likely candidate for the 40-man roster after the season.

GARIN CECCHINI is already on the 40-man roster and hit .312 in April for Pawtucket.

But pitchers made adjustments and Cecchini struggled for three months (.218). His August numbers are back to normal – a .306 average and .886 OPS.

“You’re seeing him make adjustments,” Boles said.

DEVEN MARRERO is another batter who needs to make changes. Marrero, the web-gem shortstop, was batting .291 for Portland when he was promoted to Triple-A on July 2.

The transition looked smooth when he hit .320 over the first three weeks. Since July 26, he’s hitting .127.

“He’s expanded the strike zone,” Boles said, meaning that Marrero is not as selective as he needs to be.

REMEMBER ANTHONY Ranaudo two years ago? Considered Boston’s top pitching prospect then, he struggled with injuries and arm fatigue, sinking to a 6.69 ERA with the Sea Dogs.

Now 24, Ranaudo is 14-4 with a 2.46 ERA at Pawtucket. He’s had two major league call-ups, including a win over the Yankees in his debut Aug. 1.

“That was definitely a confidence booster,” Ranaudo said. “I can’t believe the difference from two years ago.”

DRAKE BRITTON always was a pitcher brimming with potential. The lefty put it together last year, going from Portland to Boston, where he made 18 relief appearances (3.86 ERA).

Britton, 25, competed for a major league spot this spring but ended up in Pawtucket. He has done little to earn his way back to Boston, recording a 6.58 ERA and 2.04 WHIP (walks/hits per inning pitched) in 42 games.

“I ran into some bad luck but, at the same time, I haven’t been throwing the ball well,” Britton said.

Britton’s days with the Red Sox (or at least on the 40-man roster) may be numbered. After this season, he is out of minor league options.

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