The 49ers' potential next man up sounds like a humble young man.

Asked about his impressive strength Sunday, defensive lineman Quinton Dial, a 6-foot-5, 318-pound native of Clay, Ala. (pop. 9,727), smiled a bit sheepishly.

"I'm just a country boy," Dial explained.

That country boy who began baling hay as a 12-year-old could be the 49ers' man in the middle this season after starting nose tackle Glenn Dorsey tore his left biceps in practice Friday. Dorsey will undergo surgery and the team then will assess how long he could be sidelined.

Dr. Luga Podesta, a sports-medicine physician at Kerlan-Jobe Orthopaedic Clinic in Los Angeles, said surgically repaired biceps tears typically require a three- to fourth-month recovery. Given that timetable, Dorsey could return for the eighth game of the season, a Nov. 2 home game against the Rams, if he recovers quickly.

"For a professional athlete, maybe they could come back a little sooner" than three to fourth months, Podesta said. "But it's really the biology that dictates that. You just have to wait for the tendon to heal from a surgical standpoint."

Meanwhile, nose tackle Ian Williams, the 2013 season-opening starter, still hasn't fully healed from a broken ankle and extensive ligament damage he suffered in September. Williams is on the physically unable to perform list and defensive coordinator Vic Fangio said the 49ers "haven't decided" if Williams will be ready to play in Week 1.

Those injuries to players who began last season as the team's top two nose tackles have shifted the focus to Dial, a 2013 fifth-round pick who began last season dealing with an injury. Dial underwent toe surgery after his senior year at Alabama, spent the first six weeks of the 2013 season on the non-football injury list and played just 19 snaps in three games.

Now healthy, Dial, who has routinely caved in part of the offensive line during training-camp practices, says he has received compliments from teammates impressed by his brute strength. Dial, however, has been playing defensive tackle this summer. At Alabama, he occasionally played nose tackle, where Fangio noted his height could be a detriment at a position where players must have excellent leverage to handle double teams. Both Dorsey and Williams are 6-1.

Michael Macor/The Chronicle

"He's got to get his pad level down," Fangio said. "... I think he has the potential to do fine in there. We just have to get him worked in there and he has to recognize the schemes."

Said Dial: "It's going to come back to me and it's going to be second nature to me. I just need to come back hard and get used to it."

Dial won't have the spot handed it to him. Tony Jerod-Eddie, who was signed by the 49ers as an undrafted free agent in 2012, finished last year as Dorsey's backup and played 385 snaps at nose guard and tackle. Mike Purcell, an undrafted free agent who spent last year on the practice squad, is also in the conversation.

Whoever assumes Dorsey's spot won't handle full-time duty because the nose tackle comes off the field in the 49ers' nickel defense. Dorsey, for example, played just 45 percent of the defensive snaps in the 13 games he finished last year after replacing Williams.

Although it's not an every-down position, it is a demanding job that requires the strength to stand up to double teams.

"That suits me," Dial said. "I'm a physical guy. That's what I pride myself in and I bring it to the table for this team. We're known as a physical team. So I just pride myself on coming to work every day and bringing that lunch pail."