Believe it or not, Matt Kalil still has an active Twitter account.

"But I did delete the app," the Vikings embattled left tackle said Thursday, three days before he faces former Vikings All-Pro defensive end Jared Allen in a key matchup in Sunday's game against the Bears at Soldier Field.

And when did this take place?

"After the Patriots game [in Week 2], I think," he said. "I gave up three sacks and everyone wanted to kill me."

Mentally, people were doing a pretty good job slaying this young giant with the kind of words and anger that far too often accompany the protected anonymity of cyberspace. The media and the folks at Pro Football Focus kept the language clean but weren't exactly uplifting, either.

Finally, the outside chatter became too much. The fourth overall pick from 2012 knew he wasn't playing well. He knew that his surgically repaired right knee wasn't 100 percent and that it would take time to trust it again. He also knew no one cared about that last part.

"I knew I dug myself a hole," Kalil said. "And I know it's my job to get myself out of it."

And that journey won't include tapping that Twitter icon.

"It brings you down," Kalil said. "I think it's probably a maturity thing. My rookie year, when everything was great, I was looking at it to see how great people said I was.

"Last year, I struggled a little bit — although I think I played pretty well, personally — and you start to see some of the negativity. Over time, I think it affects you. Your demeanor almost goes with how people feel about you. So I've grown up a lot and I'm going great right now as far as mental toughness and facing up to adversity, which I had never faced in my career."

Here comes Jared

Neither Kalil nor Allen is Pro Bowl-bound this season. While Kalil's right knee has been slow to come around, Allen's early-season bout with pneumonia cost him one game and 17 pounds off an already-lean 256-pound frame.

Allen said his weight and strength are close to normal, while Kalil said he's also starting to feel like his old self — the old self that many forget made the Pro Bowl as a rookie.

"He's been beat a few times, but who doesn't get beat a few times?" Allen said of Kalil. "He's a good player. He has good feet. He has good technique. We're going to have to take advantage of situations because he knows me, I know him and we'll just have to see whose techniques will be better."

Allen, whose 130 sacks rank 12th in NFL history, has only 1½ sacks this season. But he may hold the spark that could keep the home crowd from turning on a disappointing 3-6 team that is returning home after becoming the first NFL team in 91 years to give up 50 or more points in back-to-back games.

Still wary

"People are saying Jared's not playing well," Kalil said. "But there's 10 or 11 plays where he's a foot away from the quarterback. I don't think he's lost a step at all. Obviously, the older you get you're not as powerful as you used to be, but he's a guy who is going to adapt to how his body is feeling and he's going to find a way to make plays."

A few early calf-roping sack celebrations by Allen and the pain of those 51-23 and 55-14 losses to the Patriots and Packers will disappear against a Vikings offense that ranks 26th in scoring.

On the other hand, a strong game by Kalil and a slow start by the Bears' 32nd-ranked scoring defense and, well, we'll let Jared explain the possibilities.

"Oooh, I don't know," he said. "Complete anarchy, maybe."

Focusing on PFF

The analytical site Pro Football Focus has been criticized a few times at Winter Park this season.

At one point, unsolicited, coach Mike Zimmer cautioned reporters to take the information "with a grain of salt" and criticized the site's accuracy because its analysts aren't privy to individual assignment responsibilities.

Sam Monson, senior analyst at PFF, counters that charge by saying most assignments are identifiable because they're obvious or able to be detected by a group of analysts who regularly consult with NFL insiders to hone their analytical craft. He also said, for example, that sacks can be blamed on multiple blockers or the quarterback for holding the ball too long.

"When we're assigning blame, it's not through blind guesswork," Monson said. "There is obvious an inbuilt error margin by not having every call. We have always acknowledged that, and our grading rule is if we're not sure, we don't guess, and we leave it 'ungraded.'

"That same error margin applies to anybody watching tape of another team, though. It doesn't stop a coaching staff breaking down their upcoming opponents. They don't know the calls, but they're well aware of the fact that they can figure it out most of the time."

In Kalil's case, PFF's site has him ranked 73rd among 75 offensive tackles. It has him with a league-high 10 sacks allowed and 34 total pressures (sacks, hits and hurries), second behind Carolina's Byron Bell (39).

Kalil questions PFF's accuracy for the reason already mentioned. But he doesn't argue with the site's ultimate conclusion on his season.

"You probably can get an accurate gauge for me [at PFF]," he said. "But if you just want an honest opinion from me, then, yeah, I haven't played as well as I could have."

Different viewpoints

Kalil said the Vikings have him down for "six or seven" sacks allowed, not 10. PFF had him with two sacks allowed but a season-high 1.4 pass-protection rating in the Vikings' last game, a 29-26 win over Washington.

Left guard Charlie Johnson also got blamed for one of the team's two sacks, either for not being stout enough on a left slide call against an inside-rushing defensive end or a miscommunication with Kalil on a stunt that both misplayed.

Johnson has gone relatively under the radar when perhaps he deserves to share much of Kalil's criticism. One particular sack in the Buffalo game that Kalil was heavily criticized for actually came when Johnson didn't slide like he was supposed to, creating a gap that Kalil couldn't compensate for based on the protection call.

"Me and Charlie are always talking and trying to get better," Kalil said. "And we will."

Knee finally healing

Kalil said his problem this year can be traced to the start of last season, when his right knee began to bother him.

"Last year, it looked like you could fit two baseballs inside of my knee, it was swollen that much," he said. "It was stiff and I couldn't even move it. The type of person I am, I'm not going to sit there and say I'm hurt. I'm trained to play through it."

Kalil had offseason arthroscopic surgery and missed the offseason workouts. He returned for the start of training camp, even though he says now that the knee wasn't ready.

"It's just pressure to play, because you feel like you're letting your teammates down if you sit out," he said. "I was telling my coach [Jeff Davidson] this the other day. When I came to camp, I was expecting to just pick up where I left off. But my knee was still killing me. You just kind of go in survival mode and abandon all technique and try to do whatever it takes to win.

"But then that develops bad habits over time and that solidifies bad techniques, and you get away from what you're supposed to be doing. I think that affected me a lot."

Slow improvement

It didn't help that across from him was Everson Griffen champing at the bit with his first opportunity to be an NFL starter.

"Everson beating me a lot in practice kind of diminished my confidence," Kalil said. "And that's where the mental games started a little bit. I wasn't confident in my ability. I wasn't confident in my knee and my ability to set. Pretty much the first half of the season, I was playing on one leg."

Kalil said the health of his right knee returned probably five weeks ago, but the confidence to push the knee didn't come until the past two games — wins over Tampa Bay, in which he allowed no sacks, and Washington.

"It's gotten a lot better the past two games," he said. "It's coming back. Just go back to my rookie year. I watch film of my rookie year every day now. I watch how I moved. What I've gone through has nothing to do with my ability. Right now, it's all up here [in his head].

"Now it's my job to get on a run and get myself out of this hole. I'll be all right."