Three critical Vikings players are officially listed as questionable, or 50/50 to play, for Sunday’s game in Pittsburgh due to injuries, but coach Mike Zimmer said all are expected to play.

Quarterback Sam Bradford, linebacker Anthony Barr and cornerback Xavier Rhodes were all limited in practices this week. Bradford’s injury is to his left knee, the same one on which he’s twice undergone surgery to repair a torn ACL in 2013 and 2014. He played all 65 snaps against the Saints, but needed to undergo an MRI this week that turned up negative, according to ESPN.

“I’m not going to talk about who’s had MRIs or who hasn’t had MRIs,” Zimmer said. “Lots of guys have MRIs. I had one, two maybe, on my knee.”

Rhodes, who could still play Sunday against the Steelers and star receiver Antonio Brown, is dealing with a hip injury suffered in practice this week and was limited on Thursday or Friday. He left the game Monday night against the Saints with heat exhaustion.

Zimmer pushed Wednesday’s practice back in an effort to give his players more rest on a short week.

Barr, nursing an injured hamstring, returned to practice on Friday after sitting out Wednesday and Thursday. The Vikings appear to be practicing as if he’ll play, including Barr on special teams drills Friday during the portion of practice open to reporters. If Barr can’t go, expect linebacker Emmanuel Lamur to take his spot in the lineup.

Remember the NFL did away with the “probable” game-day designation last year, which could theoretically lead to more players being listed as 50/50 to play. Last year’s math suggested questionable Vikings players have better than a coin flip’s chance of playing.

Nineteen of 27 Vikings players listed as questionable last season ended up playing that week.

For the Steelers, defensive end Stephon Tuitt (biceps), tight end Vance McDonald (back) and safety J.J. Wilcox (concussion) are questionable to play. Tackle Jerald Hawkins (knee) was ruled out.

A heavy Steel curtain

The Steelers offensive line might be one of the largest in football with an average weight of 317.2 pounds across their five starters. The Vikings’ average, for comparison, is 12 pounds lighter.

So when it comes to defending Steelers running back Le’Veon Bell or getting after quarterback Ben Roethlisberger, the Vikings are wary of not getting too tied up by Pittsburgh’s big men.

“Part of it is they get their arms around you and try to keep you from getting off blocks the way they do it,” Zimmer said. “We’re going to have to make sure we don’t allow them to hold us.”

The purple ‘Bus’

A Duluth youth football coach once gave C.J. Ham the nickname “The Bus,” so the Vikings fullback’s trip to Pittsburgh this weekend — for his second-ever NFL game — will be another “surreal” moment after debuting on national television Monday night.

“I got the nickname Bus, so I was just like who is this dude?” Ham said. “I looked him up as a kid and started following the Steelers just because of Jerome Bettis. It’s definitely going to be another surreal moment.”

Ham, the latest Minnesota-born and undrafted player to make the Vikings roster, played nine snaps against the Saints as the backfield’s lead blocker.

Joseph, Diggs fined

Two Vikings players were fined by the NFL after Monday night. Vikings nose tackle Linval Joseph was fined $9,115 for his face mask penalty against the Saints. Receiver Stefon Diggs received a $6,076 fine for punting the ball into the stands after one of his two touchdown catches, a league source told the Star Tribune.

The source added defensive tackle Tom Johnson was not fined for his questionable roughing the passer penalty on Saints quarterback Drew Brees.

Two Saints were also fined for unnecessary roughness penalties. Safety Kenny Vaccaro was fined $24,309 for his hit on Diggs. Linebacker Alex Anzalone was also fined $24,309 for his helmet-to-helmet hit on running back Dalvin Cook.