Reggie Bush (ankle) leaves game vs. Vikings

Bush exited the 49ers’ season-opening 20-3 victory over the Minnesota Vikings with a calf strain after being stopped for no gain on a third-and-1 running play. He limped off the field and was carted from the sideline to the locker room for further examination.

Bush is undoubtedly a versatile option in the backfield, but it didn’t take long for the 49ers to see how risky it can be to rely on him to play any significant role. It starts this week against a Pittsburgh Steelers squad that has problems in the secondary, and strengths in the passing game. Buckle up, 49ers fans, because it’s about to get mighty interesting!

Tomsula said after a day off on Tuesday, players will return on Wednesday for “C and I Day”. “We looked at that and planned accordingly”. “That is simply the details of it. That is the place we go”. We don’t have final answers yet, but the group got off to a strong start in Week 1. Here’s the parameters. Here’s the facts.

But, of course, I’m a silly over-optimist about all things 49ers, as proved by previous year when I predicted they’d go 11-5 and… yeah, also win the Super Bowl.

Following the game, Vikings head coach Mike Zimmer said his team was “out-physicaled” by the 49ers both offensively and defensively. “I love it”, Hyde said. “There’s no question that we drew the short end of the straw on this one”.

In what is the ultimate vote of confidence, former Australian Rugby League star Jarryd Hayne was given sole duties of punt returning by head coach Jim Tomsula on Monday night.

Linebacker Michael Wilhoite agreed: You re not going to hear anybody complain or give excuses before or after the game.

If they don’t… well, we don’t quite know yet, but we can guess. They’re treating and he’s getting everything checked…

“I mean, if he can play, he’s going to play”. “We better be as well”.

Above all, eyes will be on 49ers quarterback Colin Kaepernick, who is heading into a make-or-break season.

Bush hopped off the field after he was injured on his second carry against the Vikings. “He looks fine”.

Eric Branch is a San Francisco Chronicle staff writer. The Steelers will have had almost 10 days to recuperate since their season opener, last Thursday’s 28-21 loss at New England. The figures do not include a station that acquired the 49ers’ free-to-air rights.