EDEN PRAIRIE, Minn. -- The Minnesota Vikings won't have linebacker Eric Kendricks on Sunday as they try to slow down Todd Gurley and the St. Louis Rams' running game.

The Vikings ruled Kendricks out with a rib injury, and Audie Cole will start at middle linebacker in what could be a key game for both the Vikings' and the Rams' playoff chances. Kendricks won NFL Defensive Rookie of the Month honors in October, when he had four sacks, but will miss his first career game Sunday.

Strong-side linebacker Anthony Barr was "full-go" in the Vikings' short, non-padded practice on Friday, coach Mike Zimmer said. Barr, who is dealing with a low back injury, was listed as questionable but figures to play. But Kendricks' ailment is trickier, considering how much open-field contact linebackers face at their position. If the Vikings were in a playoff game, the sense I get is that Kendricks would play. But with so much time left in the season, it makes sense for the Vikings to be cautious with their promising rookie and avoid a situation like what happened to Chad Greenway last year, when he tried to play with a rib injury and wound up missing three games after breaking his ribs against New Orleans.

So Cole gets another chance to play, after doing an impressive job at middle linebacker at the end of 2013. He started the season finale last year against Chicago in place of Greenway and had 11 tackles in the win over the Bears. Cole started training camp with the Vikings' top defensive unit at middle linebacker, before Gerald Hodges (and eventually Kendricks) moved to the spot ahead of him. As the first linebacker off the bench, though, he's won the Vikings' trust.

"He's a smart guy. He's very passionate about his job," Zimmer said. "He's always looking for an opportunity to show what he can do. Most of the time, when he's had those opportunities, he's played well. [He] adds a lot of value to us, regardless of what he's doing, whether it's special teams or whatever."

Wide receiver Stefon Diggs (hamstring) is probable for Sunday's game, as are Cole (finger), defensive tackle Tom Johnson (knee), safety Harrison Smith (neck) and defensive end Everson Griffen (neck). Tight end Rhett Ellison, tackle T.J. Clemmings and center Joe Berger are all probable.

Defensive end Justin Trattou remains out with a sprained ankle, as does defensive tackle Sharrif Floyd after having surgery to remove cartilage from his knee.