Torn pectoral muscles are becoming a Vikings epidemic.

Reserve offensive tackle Carter Bykowski, an Eden Prairie native, is out for the season after surgery for a torn pectoral muscle, the team’s fifth such injury in 11 months.

The injury was confirmed by an NFL source Wednesday evening; Vikings coach Mike Zimmer said earlier Wednesday that Bykowski had shoulder surgery, but did not provide details.

Four other Vikings — Brian Robison, Josh Robinson, Phil Loadholt and Brandon Fusco — have been sidelined in the past 11 months because of pectoral tears. Loadholt, the team’s starting right offensive tackle, was placed on injured reserve Tuesday because of a torn left Achilles’ tendon.

Zimmer addressed the team’s problems with pectoral injuries earlier this summer. Only Robison’s injury occurred during weightlifting, and Zimmer said, “I don’t know if they’re preventable, but it’s my job and our responsibility to look into every possible way that we cannot have those.

“Always when we get more than one type of injuries, and especially pectoral that is … more of an unusual injury, you have to figure out,” Zimmer said in July. “We’ve researched it and we’re hopefully on top of it.”

Free-agent tackle Stephen Goodin, 26, took part in workouts a day after being signed. Goodin, 6-6 and 310 pounds, spent time with the Giants and Cowboys.

“He’s just another athlete to come in here and help,” Zimmer said. “We’ll give him a look and see. We’re going to continue to look.”

Happy returns

Cordarrelle Patterson has been the Vikings’ kickoff returner for the past two seasons, making the Pro Bowl as a rookie in 2013.

Marcus Sherels has been the team’s punt return man for four seasons, averaging 10.5 yards per return.

Other players have, and will, audition for those spots during the Vikings’ five preseason games, but it seems as if special teams coordinator Mike Priefer is comfortable with the same guys in the lead roles.

“[Patterson] knows we have to prepare in case he’s not the kickoff returner if he’s injured or if he’s involved in the offense a lot more, whatever the case may be,” Priefer said. “If he’s fresh, he’ll be back there … if he’s healthy, he’ll be back there. He knows he’ll get more touches as the preseason goes on to prepare him for the regular season.”

Sherels has been typecast as a sure-handed punt returner in his competition with rookie Stefon Diggs, who brings a bit more flash to the position, although Priefer described Sherels as “explosive,” too. Statistically, they have both been impressive through two preseason games — Diggs is averaging 24.2 yards on five returns, and Sherels 21.5 yards on two returns.

“Sherels more than likely will be our [punt] returner if everything works toward what I would like obviously,” Priefer said. “He’s [also] an excellent backup kickoff returner and he can play halfback on a kickoff return team because he’s an effective blocker as well, no matter what his size is.

“Stefon had the benefit of some really great blocking and he’s done a great job of hitting the seams. Marcus has had two pretty explosive returns himself without the benefit of as much blocking. It’s a great battle so far.”

Stephen sidelined

Zimmer said Wednesday defensive tackle Shamar Stephen had arthroscopic surgery on a knee this week, but he is expected to be ready for the regular season.

Stephen, who served as a backup last season as a rookie, entered training camp on the non-football injury list because of a left knee injury.

The Vikings have decent depth on the defensive line, and Zimmer anticipates Stephen will be ready by the Sept. 14 opener at San Francisco.

“On game day, a lot of times you can go three tackles anyway,” Zimmer said. “We’ll move guys around. [Scott] Crichton can go inside some and some of the other guys.”

Also sidelined because of injury Wednesday were safety Antone Exum (hamstring), center John Sullivan (back spasms) and tight end MyCole Pruitt (ankle).