Vikings' Aviante Collins carted off the field at practice with a left leg injury

The Vikings appeared to suffer their worst injury of training camp when tackle Aviante Collins was carted off the field with a left leg injury suffered during a live goal-line running play early in Thursday's practice.

Collins, who missed all last season while recovering from surgery to repair a torn biceps, is competing with Rashod Hill for the swing tackle job behind starters Riley Reiff and Brian O'Neill. Collins was playing left tackle when he went down and was replaced on the second unit by Storm Norton.

Undrafted out of Texas Christian in 2017, Collins impressed the coaching staff with how well he played in the 23-10 bye-clinching, Week 17 victory over the Bears that season. Needing to rest tight end Kyle Rudolph, then-offensive coordinator Pat Shurmur shifted to what he called the "muscle" formation and used Collins — whose NFL experience to that point was limited to three special teams snaps — as a blocking tight end.

Meanwhile, the Vikings claimed former Redskins guard Tyler Catalina later Thursday. The 26-year-old missed last season because of shoulder surgery and started two games at right guard in 2017. Guard Tiano Pupungatoa, a River Falls, Wis., and South Dakota State product, was waived.

What in the name of Bill Parcells is going on here, Zim?

The Parcells protege not only complimented two rookies in one answer, but he also did so without a leading question.

Asked to name some players who have "flashed" in camp so far, coach Mike Zimmer paused, thought it over and mentioned, completely unsolicited, undrafted tight end Brandon Dillon and cornerback Kris Boyd, a seventh-round pick.

"[Dillon] has shown us good things for being an undrafted guy," Zimmer said. "Kris Boyd has done a nice job. I just like his skill set, No. 1, but I also like how he's really paying attention, trying to get the finer points of the position down."

Sorry, Bill.

Being an old-school defensive mind with an emphasis on teaching defensive backs, it figures that Zimmer's a little leery of the NFL's decision to expand replay reviews to include pass interference.

Still unsure how it will work even after the league sent another explanatory video this week, Zimmer looks forward to testing the new replay rule during the preseason.

"My flags are probably going to get emptied out in the preseason," Zimmer said.

With David Morgan still on the physically-unable-to-perform list, second-year pro Tyler Conklin has been working as the third tight end behind Rudolph and Irv Smith Jr.

"He's going to be a factor in our offense this year, I believe," Zimmer said of Conklin. "I really like Tyler. He's a big guy, he runs well, he catches the ball pretty good. He's working on his blocking. … He's a good kid. Works hard. Smart. He's doing a really nice job."

Vikings Chief Operating Officer Kevin Warren leaves the team Sept. 16 to begin the transition to replacing Jim Delany as Big Ten commissioner on Jan. 1.

Warren was the NFL's first black COO and will become the first black commissioner of a Power Five conference. Although the 55-year-old Warren is only five years younger than current NFL Commissioner Roger Goodell, it's logical to think there could be a day when Warren could break another color barrier as Goodell's successor.

"I think Kevin could be [NFL commissioner]," said Mark Wilf, Vikings owner and president. "Kevin is an outstanding individual. Someone we're very proud that he's led our organization over the years. The sky is the limit as far as Kevin Warren is concerned from my personal perspective.

"A great deal of respect and admiration from our family and ownership. We know the Big Ten will have a great commissioner in Kevin Warren. He's just an outstanding not just sports executive but human being."