While Kirk Cousins grabs headlines and talking points, the Vikings’ 1B addition this offseason — defensive tackle Sheldon Richardson — is “champing at the bit” to make his own splash during Sunday’s season opener against the 49ers.

The Vikings are equally antsy to unveil the new starting four along the defensive line with Richardson, Linval Joseph, Danielle Hunter and Everson Griffen after the pass rush tailed off at the end of last season. Richardson said he’s anticipating Sunday will be the start to a “fun season” for that group.

“Just a feeling,” Richardson said.

Coach Mike Zimmer said he expects Richardson’s interior pass rush to most help the Vikings’ dynamic duo of ends in Griffen and Hunter. Eliminating quarterback Jimmy Garoppolo’s room to step up in the pocket means he’d be easier to grab for the Vikings’ edge rushers.

“He’s going to show what he can do on Sunday,” Griffen said. “Because we’ve been polishing up the craft and getting ready to let the real bullets fly.”

Rhodes questionable

Cornerback Xavier Rhodes is listed as questionable to play Sunday because of a lingering hamstring injury. But he did practice in full on Friday, indicating he probably has better than a 50-50 chance of suiting up against the 49ers.

Cornerback Mackensie Alexander (ankle) is listed as doubtful. That means rookie Mike Hughes is in line for a busy NFL debut as the slot corner and kick returner. Three Vikings have been ruled out: center Pat Elflein (ankle/shoulder), tackle Aviante Collins (elbow) and running back Roc Thomas (ankle).

‘Going to take time’

How officials will enforce the NFLs’ new helmet-use rule this season is still murky to Zimmer, who said “thankfully” the Vikings weren’t penalized for it during the preseason. In support of defense, Zimmer had sent an opponent’s penalty to the league office for review last month. Jaguars cornerback A.J. Bouye was flagged for lowering his helmet to initiate contact with Vikings fullback C.J. Ham. Zimmer said he felt it was incidental contact since Ham lowered his head.

“I’m not totally 100 percent sure. I think I know,” Zimmer said. “I’m sure there’s going to be some calls where you’re scratching your head or some calls where you think it should be and it’s missed. I think it’s going to take them a little bit of time to keep telling us examples of what they’re going to call.”

Quick hits

• The Vikings reportedly tried to claim defensive end Anthony Zettel, who had 2.5 sacks for the Lions in two games against the Vikings last season, according to former NFL front office employee Field Yates, who now works for ESPN. Zettel was awarded to the Browns, No. 1 in waiver wire priority; the Packers and Chargers also tried to add him.

• The Vikings waived three players off injured reserve Friday after agreeing to injury settlements: offensive lineman Josh Andrews, cornerback Craig James and running back Mack Brown.