If you were to name the most disappointing players for the Vikings this past season, left tackle Matt Kalil's name would be among the first that came to mind. That's what happens when you set the bar high with a Pro Bowl season as a rookie then regress to one of the league's leakiest left tackles in pass protection in your third season.

No, the 2014 season didn't go quite like Kalil had planned. He had surgery on his left knee in May and wasn't able to practice with the team during spring organized team activities and the June minicamp. That preceded a poor first half of the season for Kalil, who feels that being under so much scrutiny will aid his development down the road.

"I've never really had any kind of injuries my whole career and I think you kind of take that for granted, playing healthy," Kalil said last week as Vikings players cleaned out their lockers. "So as far as being mentally tough and the adversity I had to face this year, I think it made me a lot stronger mentally. It's something that you learn from. … Players have bad years. It's not the end of the world for me. What I see is an opportunity to go into the offseason and correct what I can correct and have a great year next year."

Kalil said he thought he could play with the knee injury, but because he knee "was swelling up a lot," he opted to have surgery during the spring, which sidelined him until training camp. He said the lack of technical refinement affected his play once the season rolled around.

"If you're a quarterback and you don't throw for six months and go into camp, you're not going to be as sharp as you can be. It goes with any position, just getting technically sound," Kalil said. "My whole career, that's what I strived on is in the offseason doing a lot of fundamental stuff and working on my technique. This was the first offseason not doing that and it showed."

Kalil allowed 10 sacks in the first nine games of the season, according to Pro Football Focus, an analytics site that Kalil was critical during the season. It's worth noting, though, that two players — New England's Chandler Jones and Detroit's Ziggy Ansah — won conference Defensive Player of the Week awards after lining up against Kalil.

"It took me until after the bye week to kind of figure it out and get my technique back," Kalil said. "I played a lot better but it's still not the level I'm capable of playing."

Kalil did play a little better after the Week 10 bye week, allowing just two sacks over the team's final seven games. But he was far from dominant, giving up 21 total pressures over that span.

Overall, Kalil was beaten for 12 sacks on the season, according to Pro Football Focus. That was the most among NFL offensive tackles. Only Dolphins rookie tackle Ja'Wuan James allowed more total pressures, with 58 to Kalil's 55.

While Kalil can quibble with Pro Football Focus over their credentials when it comes to evaluating his play, he does concede that he did not meet the expectations that go with being a former top-five pick and a Pro Bowl pass protector just two seasons ago.

"Obviously I set the bar high my rookie season so that's the expectations of me for the rest of my career," he said. "As far as I critique myself, I know how I'm doing and the level that I play at. It's just about getting my body on that same level and being super sharp when OTAs come and keep sharpening that skillset so when the season comes I'm not behind and I'm ahead of the curve and ready to go."

The Vikings remain invested in Kalil, a young player who still has plenty of potential at a premium position, and they are expected to pick up his fifth-year option in May, keeping him under contractual control for the next two seasons. But Kalil's play must improve markedly for him to show the Vikings that he is worthy of a lucrative contract extension in the next couple of years.