ENGLEWOOD, Colo. (AP) — Kyle Orton only needs to worry about correcting his mistakes, not looking over his shoulder.

New Broncos coach Josh McDaniels is standing behind his struggling quarterback, whom Denver acquired this spring in a trade with Chicago. That deal sent Pro Bowl passer Jay Cutler to the Bears after his relationship with McDaniels soured.

Orton threw three interceptions on three straight first-half series in Denver’s 17-16 exhibition loss to the San Francisco 49ers, while his backup, Chris Simms, threw two touchdown passes.

McDaniels said it’s too early to think about pulling the plug on Orton, who was booed for his poor play and two interceptions in a free scrimmage at Invesco Field last week, dampening what was supposed to be a night of fun.

“I feel very confident where we’re at,” McDaniels said after the game. “He made a few mistakes, but we’re not going to go into this thing after the first preseason game and start tailspinning and doing this and that and making knee-jerk reactions.”

The bigger issue facing the Broncos could be the health of top draft pick Knowshon Moreno, who went to the locker room in the second quarter with a leg injury. He was scheduled for an MRI exam on Saturday.

McDaniels didn’t hesitate to play Moreno against the Niners even though he had practiced just five times after ending an eight-day holdout by signing a five-year, $23 million contract.

The Broncos return to the field Sunday, and wide receiver Brandon Marshall, fresh off his acquittal in a misdemeanor battery trial in Atlanta, could return for the first time since pulling up lame on a deep route Aug. 2.

As for his quarterback, McDaniels named Orton his starter in June. Coaches say he’s come a long way in learning the intricate Patriots’ style offense that requires the quarterback to make plenty of decisions at the line of scrimmage.

But he’s struggled to put together any consistency, throwing several interceptions in one practice and then looking picture perfect the next.

“I’m not pressing at all,” Orton said. “I’m trying to get comfortable with the offense and get ready for the first game.”

And he fully expects to be the starter when the Broncos open their season at Cincinnati on Sept. 13.

“I’m not worried about it,” Orton said when asked about the possibility of losing the starting job. “I’ve got a lot of confidence in me, and my team has a lot of confidence in me.”

Orton’s first interception came in the end zone when he tried to lead tight end Daniel Graham with a pass in zone coverage, ruining what had been an impressive and long drive on the Broncos’ first possession.

His second interception — by former Broncos cornerback Dre’ Bly — led to San Francisco’s first touchdown, a 3-yard pass.

“I don’t want to make those decisions and have three interceptions, but for the most part I felt very comfortable and felt we did a lot of good things on offense,” Orton said.

McDaniels said there were plenty of mistakes to go around.

“We’ve got things we can fix and improve upon. I can definitely improve too. I told the players that. It starts with me,” he said.

Not only does Orton have his coach’s confidence, but Simms has his back, too.

“Kyle didn’t struggle,” Simms insisted. “I really don’t think he did. He moved the ball well in all his series, and I think he’ll tell you the those three throws are ones he makes every day in practice. He’s a good player, and he’ll bounce back and be ready for next game.”

Niners coach Mike Singletary also praised Orton, who is 21-12 as a starter in the NFL.

“I think our guys did a pretty decent job of being where they needed to be and maybe the quarterback thought he saw something. Orton is a better quarterback than a lot of people think he is,” Singletary said. “He’s very solid, very consistent and I think our DBs did a pretty decent job.”