Vikings left tackle Matt Kalil surrendered a sack in Sunday's 20-9 loss to the New Orleans Saints and has been beaten for three in his past two games. But coach Mike Zimmer is not ready to sound any alarms when it comes to Kalil, who two years ago was the fourth overall pick in the NFL draft.

"For 93 percent of the game, he plays pretty good. But unfortunately, the three or four bad plays he has show up and [fans and media] get on him," Zimmer said Wednesday. "So I'm not that discouraged as everybody else is. We'll just try to get those four bad plays out of there and keep going."

Through three games, he has given up three sacks and has allowed more pressures than any other NFL offensive lineman, according to Pro Football Focus.

On Monday, Zimmer hinted that it might be a mental issue, saying that Kalil needs to have a shorter memory — like a top cornerback — if he has a bad play. Wednesday, Zimmer said it was a technical issue.

After holding up well against All-Pro defensive end Robert Quinn and the St. Louis Rams in Week 1, Kalil has allowed 12 quarterback pressures the past two weeks, according to Pro Football Focus.

That has led to criticism from fans and media alike, and Zimmer is well aware of the scrutiny.

"I know everybody's on this Kalil kick," he said. "I think it's easy to see some of those things on TV or sitting in the press box or on the field, guys get beat. It's easy to see. We've had corners get beat. We've had linebackers get beat. We've had guards get beat. But everybody's on this Kalil kick."

Cassel, Fusco put on IR

The Vikings announced Wednesday morning that quarterback Matt Cassel and starting right guard Brandon Fusco were headed to injured reserve, ending their seasons.

Cassel, who broke his left foot, has an appointment in Charlotte today with renowned specialist Dr. Robert Anderson. Fusco, meanwhile, will be undergoing surgery to repair his torn pectoral muscle.

Zimmer revealed a sliver of good news, though, when he said that the team probably won't have to place tight end Kyle Rudolph, who had surgery to repair a sports hernia Tuesday, on injured reserve with a return designation, something that would require Rudolph to sit out at least eight weeks.

"We're hopeful that he'll be back soon," Zimmer said. "We're anticipating it's not going to be that long."

Greenway frustrated

Outside linebacker Chad Greenway, who left in the fourth quarter of Sunday's loss, did not practice Wednesday due to a broken left hand and a painful broken rib. Greenway, whose status for this weekend is in doubt, said he was frustrated that the injuries affected his play against the Saints.

"Sometimes you can't deal with them as much as you thought you could have or they become just too much," Greenway said.

Nose tackle Linval Joseph (shoulder) and cornerback Josh Robinson (hamstring) did not practice. Another new addition to the injury report was safety Harrison Smith, who was limited by a knee injury.

Outside linebacker Brandon Watts (knee) also was limited. Defensive tackle Sharrif Floyd (shoulder), outside linebacker Michael Mauti (foot) and wide receiver Rodney Smith (hamstring) participated fully.

Green dot for Barr?

With Greenway potentially out for Sunday's game against the Atlanta Falcons, rookie outside linebacker Anthony Barr could be the one who wears the green dot on his helmet, meaning that he is the lone defender who will have the play call radioed from Zimmer to the headset inside his helmet.

"It's something I'm still working on," he said. "Obviously, I don't have the defense mastered by any means, so it's a definitely a challenge and I just have to continue to try to get everybody set up and ready to roll."

Etc.

• The Vikings promoted tight end Chase Ford and guard Austin Wentworth to the 53-man roster and signed quarterback McLeod Bethel-Thompson and tight end Ryan Otten to the practice squad.

• Vladimir Ducasse was lining up at right guard in the portion of practice open to media.

• Cornerback Xavier Rhodes, who had a hamstring injury, no longer is on the injury report.