The 49ers’ season took an unexpected twist when wide receiver Michael Crabtree made a cut during a 7-on-7 drill Tuesday.

As he planted upfield after going in motion, Crabtree sustained a complete tear of right Achilles tendon during the team’s first OTA practice of the spring. He had surgery this morning at Stanford Hospital and Jim Harbaugh said he does not expect Crabtree’s injury to sideline him for the season.

According to multiple reports, Crabtree will be out six months, which would put his return in late November, around Week 12.

According to Harbaugh, Dr. Tim McAdams, who performed the surgery, provided the fifth-year wide receiver with reason for optimism after he awoke. Harbaugh visited Crabtree at the hospital and was about 30 minutes late to this afternoon’s practice.

“The good news is, he woke up from the surgery and the first thing he asked was doc how it went,” Harbaugh said. “(McAdams) talked about the success of the surgery and that he didn’t anticipate that he’d be out for the year and (Crabtree’s) comment to that was that he’s got no choice but to be back. Every day now is a healing day, and that starts today.”

In the interim, the 49ers have one established, healthy wide receiver in Anquan Boldin, who is not attending OTAs this week because of a prior commitment, Harbaugh said. Wide receiver Kyle Williams and Mario Manningham are recovering from knee injuries sustained late in the 2012 season and only Williams is expected to be ready for the start of training camp.

Other options include A.J. Jenkins, last year’s first-round pick who doesn’t have an NFL catch, and Ricardo Lockette, 27, who spent last year on the practice squad after he was signed in October. Lockette, entering his third NFL season, has two career catches. Both Jenkins and Lockette lived with Kaepernick this offseason in Atlanta, where they trained together for about two months.

Harbaugh declined to discuss the possibility of the 49ers re-signing Randy Moss or adding another free-agent wideout. He offered his standard response to such questions: He would only discuss the players currently on the 49ers roster.

“We’re excited for the young receivers that we have,” Harbaugh said. “I really feel that somebody is going to emerge there, because they have to. Competition will create that, and we’ll look forward to watching that.”

Those young wideouts will attempt to show Colin Kaepernick they have what it takes to fill the void created by Crabtree’s injury. Kaepernick targeted Crabtree with 94 passes last year, 55 more than any other pass-catcher on San Francisco’s roster.

Today, Kaepernick was asked why Crabtree became his preferred target: “He got open,” Kaepernick said.