Angels bust out nine run inning in Garrett Richards’ return to Boston

What started well did not end that well for Angels right-hander Garrett Richards on Friday night.

Richards held the Boston Red Sox to three runs in the first six innings of an eventual 12-5 victory at Fenway Park, a game in which a struggling Angels offense busted out for nine runs in the fifth inning, sending 13 batters to the plate, amassing six hits, including two home runs, three walks and batting for 39 minutes.

Then Richards gave up two runs on three hits, a walk and an error in the seventh and was pulled after Dustin Pedroia hit a line drive off the back of his surgically repaired left knee.

Richards was fine, but the Angels held a six-run lead at the time, and he was not happy about leaving a bases-loaded, no-outs mess for reliever Jose Alvarez to clean up.

“I’ve got to be better than that,” Richards said. “Having a lead like that, you don’t want to get caught just pitching to contact. Tonight was just one of those nights.”

As frustrated as Richards was as he walked off the mound, at least he was able to do so on his own terms.

The last time Richards exited Fenway Park, last Aug. 20, he was strapped to a gurney and wheeled off on a stretcher, his left leg writhing in pain and his teammates fearing he might have suffered a career-threatening injury.

Richards caught a cleat in the dirt while running to cover first and fell awkwardly to the ground, his left knee twisting and buckling as he tried to break his fall.

The soundtrack from that fateful night, when Richards ruptured his patellar tendon, an injury that would require surgery and a grueling seven-month rehabilitation, still plays in his head.

“It sounded like a Pillsbury biscuits tube, you know, when you open it and it explodes?” Richards said. “That’s what it sounded and felt like, the release of pressure and the vibration going all the way up your leg when it popped. It was the sound of my knee unraveling. It was gross.”

The Angels won that night, but Manager Mike Scioscia called it the most hollow victory since Kendrys Morales shattered his left ankle jumping into home plate after a walk-off grand slam in 2010.

“All of our hearts sank because we knew it was a really serious injury,” Scioscia said of Richards.

“You get a pit in your stomach when you see a player suffer a possible career-threatening injury.”

Nine months later, Richards seems fine physically. He has a slight hitch in his gait, but he’s 4-2 with a 2.98 earned-run average in seven starts. And there do not appear to be any mental scars, even after returning to the scene of the crime, so to speak.

“This was just another outing,” Richards said. “My knee and the injury are in the past. I don’t think about it anymore. I don’t notice it when I pitch.”

Still, as catcher Chris Iannetta said, “It was good to get this one under his belt, coming back here after that catastrophic injury. He worked his butt off to come back all off-season. To come back that quick and [to pitch as well as he has] is a tribute to his work ethic and drive.”

Iannetta helped make sure Richards’ return to Fenway was triumphant, hitting a three-run homer off reliever Matt Barnes in the fifth. Erick Aybar added a two-run homer off Barnes.

Mike Trout and Kole Calhoun had run-scoring singles, and David Freese hit an RBI double in the fifth off Rick Porcello, who was on the mound the last time the Angels scored nine runs in an inning, against Detroit on April 20, 2013.

The Angels were tied for last in the American League in runs and last in on-base-plus-slugging percentage, but a fifth inning like Friday night’s could spark them.

“It definitely changes the mood,” Iannetta said. “Everyone was a lot looser and having more fun after that inning. Hopefully that attitude continues into [Saturday]. It takes some of the pressure off, guys play a little more free, and we start squaring balls up even more.”

mike.digiovanna@latimes.com

Twitter: @MikeDiGiovanna