Vikings offensive line coach Jeff Davidson has a preferred cliché he’ll trot out to keep from overextending his praise for a player’s potential.

“The proof,” Davidson will say, “is in the pudding.”

Well, if that’s true, the Vikings have five 300-pound tubs of potential pudding protecting Teddy Bridgewater. Their ability, or lack thereof, to prove themselves will help determine whether the Vikings taste the playoffs or end up just spilling pudding all over themselves.

“Our offensive line has played well [in the preseason],” offensive coordinator Norv Turner said. “We identified some things for them to do to get better, and I think the culmination of those things is showing up.”

Yes, but that was before Turner had learned that John Sullivan, the NFL’s leader in consecutive starts by a center (57), would miss at least eight weeks following back surgery. Joe Berger, who stepped in as the starter when Sullivan went down on Aug. 18, is a highly regarded veteran backup, but, as Davidson says, the proof lies in the regular season.

The Vikings could be good, bad or ugly up front. At this point, here’s what we know:

• Left tackle Matt Kalil ranked among the worst tackles in the league a year ago.

• Left guard Brandon Fusco missed 13 games because of a torn pectoral and is making the switch from right guard.

• Berger was primarily a center in Miami before joining the Vikings in 2011. He started 20 games there, including 14 in 2010, but 17 of his 18 starts with the Vikings have come at either left guard or right guard, including nine at right guard a year ago.

• Right guard Mike Harris is a career tackle who has played only one regular-season game at guard.

• Right tackle T.J. Clemmings is a rookie who was forced into the starting lineup when Phil Loadholt tore his left Achilles’ tendon.

• The backups are young and inexperienced.

Although the right side of the line has drawn most of the attention this preseason, Kalil’s performance as Bridgewater’s blind-side protector will come under scrutiny — good or bad — soon enough.

A year ago, Pro Football Focus ranked Kalil 81st out of 84 tackles. Kalil disputes the site’s ability to grade accurately but doesn’t deny that 2014 was his worst season by far.

Kalil has blamed it on knee issues. With time to heal and further procedures designed to strengthen the knees, Kalil played well during the preseason.

“My evaluation always is, ‘Did his guy affect the play in a negative way?’ ” Turner said. “Matt’s had very few plays where his guy has had a negative effect on the play.”

Overall, the preseason protection was solid. Fusco has been a noticeably sturdier presence next to Kalil.

“Yes, Brandon can help on that side,” Davidson said. “But only Matt can make Matt a good player. We need five guys who are able to take care of their own responsibilities and come together as a unit.”

Sullivan was expected to maintain consistency while supplying leadership and scheme direction to the younger players, but that now falls to the 33-year-old Berger, a veteran backup entering his 11th season.

“Joe’s a good player; That’s why we’ve had him here,” Kalil said. “He’s going to get the job done. He’s a physical, tough player. He’s got years of experience. It’s a good replacement to replace Sully with. I’m not too worried about it. … It’s been pretty smooth so far.”

Harris is a tackle-sized right guard who the team is high on at that position.

“He is a big man for a guard,” Davidson said. “But he’s done a nice job of working hard and keeping his pad level low. He just needs to continue doing what he’s doing.”

And then there’s the biggest piece of the pudding pie: Clemmings.

The former first-round prospect was sent tumbling to the fourth round of the draft after a long-ago foot fracture was discovered at the scouting combine. Clemmings said he never felt the injury or missed any time because of it.

“And he’s done nothing that would make me think he has any health issues,” Davidson said.

Clemmings is a better, more fluid athlete than Loadholt. But, as Turner said, “the one thing T.J. lacks is experience.”

And without experience, there’s no proof in the … well, you know.