Saleh and Mullens show well, with an eye on next season

Sunday was SYB (Save Your Butt) Day at Levi’s Stadium for several 49ers.

The 49ers are 3-10 after the 20-14 win over the Broncos, and that victory and the final three games are all about proving you deserve to return next season.

The testing Sunday was positive for at least two men: defensive coordinator Robert Saleh and quarterback Nick Mullens.

Saleh, in his first season as a coordinator, took some heat off his seat as the 49ers held the playoff-hopeful Broncos to 274 yards total offense, and held rookie running back Phillip Lindsay, averaging more than 8 yards per carry his past two games, to 30 yards on 14 carries.

Mullens took a significant step forward in his quest to win a job next year as Jimmy Garoppolo’s backup. Mullens was 20-for-33 for 332 yards and two touchdowns, with a passer rating of 102.1. His one interception was on a tip.

Head coach Kyle Shanahan made it clear during the week that everyone, players and staff, is on double-unsecret probation the rest of this season and next camp. Asked if Mullens is an NFL-caliber quarterback, Shanahan said he wasn’t sure. He said Mullens and C.J. Beathard are even in that race.

That was hard news to many fans, who see the plucky Beathard as a sack machine and the plucky Mullens as a playmaker-in-the-raw.

Shanahan’s lukewarm evaluation hasn’t fazed Mullens, who probably unwound after Sunday’s game by cranking crowd noise into his headphones and shouting play calls. I hope he didn’t take the train home. Fighting for a job? “I’ve been fighting for my job since the day I got here,” Mullens said.

True story. The 49ers signed him as an undrafted free agent. Mullens had a sensational debut in a rout of the Raiders, but was less spectacular since then during a three-game losing streak. However, Mullens has passed for 748 yards in the past two games, the biggest two-game yardage totals since Joe Montana in 1990.

“My mind-set doesn’t change,” Mullens said. “Really, just trying to work hard in whatever my role is for this team . ... Whatever my role is, I’m going to do it to be best of my ability. I’m lucky and honored to do that.”

Jobs are still on the line, and it’s clear that Shanahan intends to let nobody become complacent. Asked about Mullens on Sunday, Shanahan said, “I thought he played well. He did some good things and was one of the reasons we won.”

Not exactly effusive praise. No worries. Just give Mullens his headphones and get out of the way.