Blair Walsh will get a little tough love from Vikings coach Mike Zimmer this week after Walsh’s unsteady preseason kicking spilled into the regular-season opener at San Francisco.

Zimmer said Tuesday he wasn’t considering bringing in another kicker as competition for Walsh, but “I’m bringing in consideration for him to pull out of this thing and kick like he’s capable of kicking.”

Walsh missed a 44-yard field-goal attempt on the Vikings’ opening possession Monday night, and later Zimmer decided to forgo a 48-yard attempt on fourth-and-3. Walsh did score the Vikings’ only points in a 20-3 loss with a 37-yarder in the fourth quarter.

But the third-year kicker, coming off a season in which he ranked last in the NFL with a .743 field-goal percentage, was only 5-for-11 in the preseason and also missed an extra point.

“He didn’t kick very good in pregame,” Zimmer said. “I don’t know, he hit 28 out of 28 in practice last week, so he’s got to carry it to the game … it’s worrisome.”

Rough opener

Adrian Peterson’s season debut was a clunker, with 31 rushing yards on 10 carries, 21 yards on three receptions and one glaring whiff in pass protection when quarterback Teddy Bridgewater got sacked.

“I don’t think he looked tentative,” Zimmer said about Peterson. “I think he was aggressive trying to get to the hole and maybe trying to get to it a little bit too fast at times.”

As for Peterson’s pass protection, Zimmer said, “He’s been working real hard at it. He’s gotten a lot better, in my opinion, than what he was.”

Obviously Peterson prefers running the ball from a traditional tailback set, which he did on six of his carries. Four carries came out of shotgun or pistol formation, and after the game Peterson said he was “a little hesitant a couple of times coming out of the shotgun.”

It was Peterson’s first game since the opener last year, after which he was sidelined by legal issues.

“It felt good to play football and take some hits,” he said, “[but] it was definitely embarrassing to come out and play the way we did as a group tonight.”

No praise coming

Gerald Hodges got his first start at middle linebacker between veteran Chad Greenway and second-year pro Anthony Barr, who led the team with 12 tackles. Asked to assess his linebackers, Zimmer said, “Average. At best.”

“We ran under blocks. A bunch of times the fullback came outside the tight end and we stayed inside and tried to go underneath and make a play; we didn’t [cover] the boot[leg] very well; we didn’t get off blocks good enough. Want me to keep going?”

Said Greenway: “We came in and we got beat up a little bit. From a defensive front-seven point of view, it obviously wasn’t good enough. Not one that we want to have on tape.”

Zimmer was asked if he would consider using rookie middle linebacker Eric Kendricks more.

“He didn’t play that good either,” Zimmer said. “It was equal opportunity last night.”

Etc.

• The Vikings-49ers game earned an 8.8 rating and had 14,330,000 viewers, making it the most viewed “Monday Night Football’’ doubleheader late game ever. It also was the first time the second game of the doubleheader had better ratings than the first; the Falcon-Eagles game did an 8.5. Locally, the Vikings game was shown on Ch. 4 and ESPN and had a combined 31.3 rating.

• One of the lowlights of Monday’s game was when Bridgewater ran directly into rookie tackle T.J. Clemmings in the backfield while scrambling, leading to a sack.

“Nobody played a perfect game,” center Joe Berger said. “We didn’t want it to end up the way it did, but you have to come back the next play. If you start thinking of the previous play, you are going to go in the tank.”