A tackle class that could produce the fewest first-round picks since 2006 and a center class si.com draft analyst Tony Pauline refers to as a “one-player crop,” is offset by one of the best guard groups in recent memory.

“He’s the only sure thing,” Pauline said of USC offensive tackle Matt Kalil, who Pauline expects the Vikings will make the third overall pick. “They have to take him to protect Christian Ponder.

“You’ve got a lot of guys that could be good, but they’ve got question marks to them,” Pauline added in summary of the tackle class, which appears to project three, maybe four, of its members to be first-round selections.

Stanford’s Jonathan Martin and Iowa’s Riley Reiff are the other two “first-round” tackles. From a group that includes Ohio State’s Mike Adams, Mississippi’s Bobby Massie, Florida State’s Zebrie Sanders and Auburn’s Brandon Mosley, another tackle might be selected in the first round.

Kalil is clearly the class of the group. Some have compared him to former USC star Tony Boselli, the second pick of the 1995 draft.

“He’s a sure thing as a pass protector. He has to improve his run blocking. He’s been dominant for two years,” Pauline said of Kalil, 6-6, 300.

Pauline likes three lesser-known tackles as developmental players: Donald Stephenson of Oklahoma, Justin Anderson of Georgia and James Carmon of Mississippi State.

 Stephenson, 6-6, 307, wasn’t even considered draftable heading into last season. “He had a terrific year; tremendous combine. He’s going to be a very good player down the road,” Pauline said.

Anderson, 6-4, 335, is a big, strong right tackle, a late-round prospect for a team willing to invest time and patience into Anderson’s development.

Carmon, 6-5, 334, is a junior college transfer, a former defensive lineman that was moved to left tackle and began to blossom. He has a great frame and is athletic. He could be a steal for somebody late in the draft.

What the tackle class lacks in blue-chippers, the guard class offsets with what Pauline refers to as a “tremendous” collection of talent, led by Stanford’s David DeCastro and Georgia’s Cordy Glenn. They are the first-round prospects of the class, but Pauline believes as many as 10 guards might be drafted in the first 100 picks.

It’s a guard class that offers a lot of versatility. Glenn can play every position on the line but center, DeCastro and Iowa State’s Kelechi Osemele each can play right tackle, and Jeff Allen, who projects to guard in the NFL, was a left tackle at Illinois.

Need a center? You better get your guy early.

“It’s awful,” Pauline said of the center class. “You got Peter Konz of Wisconsin, then the bottom drops out. Center is a one-player crop.”