The Sports Xchange

SANTA CLARA, Calif. — San Francisco 49ers coach Jim Tomsula is a little like a stranger sitting at the high-stakes poker table for the first time.

When it comes to the 49ers’ dismal offense this preseason, you have to wonder:

Is this guy showing us all of his cards?

Or is he already a world-class bluffer?

Chances are we won’t know until the 49ers snap the ball for the first time on Sept. 14 in their regular-season opener against the Minnesota Vikings.

For now, the rookie head coach is keeping his cards close to the vest.

Tomsula admitted Sunday, a day after his club’s poor offensive effort in a 19-12 preseason loss at Denver, that “we haven’t game-planned.”

As part of that philosophy, quarterback Colin Kaepernick has not been given the ability to audible out of plays that don’t look promising at the line of scrimmage.

So is the struggling offense nothing more than an inability to guess which alignment the opponents will be in? Or is that excuse just part of the new coach’s bluff?

Based on the first team’s performance this preseason, and especially in an extended look in Saturday’s loss, it doesn’t appear as if Tomsula is holding much of a hand.

Quarterback Colin Kaepernick didn’t complete a pass for the first 29-plus minutes of Saturday’s game. When he finally connected on a couple in the final seconds of the half, they went for just 13 yards.

Before that, the 49ers had gone their first three offensive series of the game without a single first down.

The 49ers ended the first half with just three points, extending the first-team offense’s string of consecutive non-touchdown series in the preseason to eight.

Tomsula didn’t think the quarterback was at fault.

“O-line-wise, we had a little bit of a struggle,” he understated.

Kaepernick was sacked twice in the half, including once for a safety.

“There’s not any concern,” Tomsula insisted of an offensive line that’s looking to replace Mike Iupati at left guard and Anthony Davis at right tackle. “That’s what the preseason’s for.”

–Saturday’s matchup between a guy who sat out all of last season and one of the league’s standout players was an absolute mismatch.

49ers linebacker NaVorro Bowman owned Broncos quarterback Peyton Manning.

Bowman was so good, 49ers coach Jim Tomsula forgot all about his supposed 10-play limit and watched in joy as the former three-time All-Pro played 42 snaps in San Francisco’s 19-12 loss to the Denver Broncos.

Don’t be misled by the score. The Bowman-led 49ers defense dominated the first half, keeping Manning’s vaunted offense out of the end zone.

“He was just having a blast,” Tomsula said of the decision to let Bowman keep playing. “He would have played all night if we had let him.”

Bowman, who suffered a career-threatening knee injury in the NFC Championship Game at the end of the 2013 season, finished the half with two sacks and a game-high nine tackles.

In his mind, the most significant aspect of the brilliant performance was that it had occurred without his knee brace on.

“I took that chance and I felt great,” Bowman reported. “Keep taking the next step. It responded well for me. I was just selling out all the way and not thinking about (the knee).”

–If there was good news from the game other than the defensive effort, it was that the club reported no significant injuries. The 49ers also received good news upon returning to their training site Sunday. Following a doctor’s examination, injured center Daniel Kilgore has gotten the thumbs-up to begin light workouts.

The starter hasn’t played since suffering a broken leg in the 49ers’ fourth game of the 2014 season on Oct. 28. He remains questionable for the Sept. 14 opener.