Kyle Shanahan talks Fred Warner and Pierre Garçon as 49ers prepare for Vikings

The San Francisco 49ers will be without Reuben Foster for the first two games of the season. The NFL suspended the star linebacker for violating the league's policies on substances of abuse and personal conduct. Head coach Kyle Shanahan said on Friday morning during an interview with KNBR that the chances of Malcolm Smith playing on Sunday against the Minnesota Vikings are 50/50.

Needless to say, the 49ers have some issues at linebacker heading into their season opener. Shanahan feels confident that the team is prepared no matter what the lineup looks like on Sunday. Much of that has to do with an outstanding offseason from rookie Fred Warner.

"It's something we are prepared for," Shanahan said on the "Murph & Mac" show. "We didn't know whether Reuben was going to be out one game, two games, the whole year, we weren't sure. We were able to re-sign Brock (Coyle), who stepped in and did a great job for us last year and that's also why we invested a draft pick in Fred Warner.

"It puts a little bit of pressure on some other guys. They've got to step up, and I'm pretty confident that they will."

All signs are pointing toward Warner lining up at the MIKE linebacker spot when the 49ers defense takes the field against the Vikings. How is the rookie mentally handling his first NFL career start, which also happens to be his first game in the pros?

"I'm not worried about Fred," Shanahan answered. "Fred, he comes in, he doesn't act like a rookie. He's handled himself very well. He didn't come in just celebrating that he got drafted into the NFL. He came in really obsessed with earning a spot. He's owned his craft. He's learned the system inside and out.

"He had to battle some injuries throughout training camp, but he battled through them, practiced through them, and I think he's got himself in a good position where he's given himself a chance to be successful this Sunday."

While Fred Warner is the youngest player on the active roster, edging fellow rookie D.J. Reed by eight days, wide receiver Pierre Garçon is one of the most experienced on the team. Garoppolo didn't have an opportunity to play with Garçon during his five starts last year. The receiver's season ended early due to a neck injury.

"As you know, Pierre was a huge part of our team last year before he got hurt," Shanahan said. "When we were going through that tough stretch, he was really the guy who was giving us the chance to be in all those games. We were really leaning on him.

"When we lost him, it was a huge blow for us, and it put a lot of pressure on a bunch of young guys. It was stuff that we didn't enjoy going through, but we got better from it, and I think we've got a better group this year because we did put a lot of that pressure on those guys when P left.

"Now to have Pierre back and just to have his presence, his toughness — I mean, Pierre, when he's out there, he changes the mentality of our whole offense because I think it's pretty special when your receiver is one of the toughest guys out on the field."

The 49ers and Vikings kick off the season from U.S. Bank Stadium on Sunday at 10 a.m. PT (12 p.m. CT).

You can listen to the entire conversation with Shanahan below.