The club added a third interior offensive lineman (Cody Wallace) in the fourth round.

The defensive lineman, Balmer of North Carolina, is not the kind of player to generate a pass rush. But he is considered a powerful presence who can tie up blockers, enabling his teammates to make plays.

Balmer is a strong enough presence to move the pocket, but he is not regarded as a pass-rush threat. He recorded just 3.5 sacks as a senior. But Nolan said he expects Balmer to enable others in the 49ers’ front seven better opportunities to get to the quarterback.

"I’d hope so,” Nolan said. “If (an opponent) spends two guys on (Balmer), that certainly helps.” Nolan said a player such as Balmer, who can play nose tackle or defensive end in the 49ers’ 3-4 defense, will have an impact on those behind him, too.

“Patrick Willis is arguably the best defensive player in the league,” he said. “The guys in front of him have a lot to do with how good those guys are. This was key in protecting the guys that we think are the foundation of what we do.”

The 49ers used their second-round selection to take Rachal, an offensive guard of Southern California. Rachal intended to return for his senior season, but a family emergency forced him to enter the NFL draft. Rachal’s mother developed a tumor in her stomach, and the family does not have health insurance.

The 49ers are woefully thin on the offensive line. Linemen Justin Smiley and Kwame Harris left as free agents in the offseason. Guard David Baas, slated to be the starter at right guard, is expected to miss a portion of training camp. Baas underwent surgery on a torn pectoral muscle on Friday after a weightlifting injury.

“We knew going into the draft that was an area we wanted to add some depth,” Nolan said. “(Baas’ injury) wasn’t the deciding factor.”

Eight offensive linemen were selected in the first round, prompting the 49ers to select Rachal in the second round.

“When it all started back in February, the first thing Scot (McCloughan) said to me before going to the combine was, ‘I think this guy is a like a poor man’s Larry Allen’

“I started to wonder what he was saying. Does that mean he’s going to play 14 years? Or does that mean he’s going to be a big, athletic mauler that’s going to the Hall of Fame? I don’t know.”

Allen is contemplating retirement after 14 seasons, the past two of which were with the 49ers.

Best Pick:   DL Kentwan Balmer (North Carolina). The 49ers did not expect Balmer to be available at the end of the first round. There was a point in which the club considered trading up to get him, coach Mike Nolan said. But the 49ers held tight at No. 29 and selected him. Balmer is the first defensive lineman the 49ers have taken in the first round since Andre Carter in 2001.

Could Surprise:   LB Larry Grant (Ohio State). Even though he was a seventh-round draft pick, Grant has a chance to make an immediate impact. Grant will compete for the starting job at the strong inside linebacker spot. At the very least, he should make contributions on special teams.