Coach Kyle Shanahan said he will take his time on making a decision on his starting quarterback -- Nick Mullens or C.J. Beathard -- when the 49ers return to action.

Shanahan said he will first inform the players of his decision of which quarterback will start in the Week 10 game against the New York Giants on Monday, Nov. 12.

"The players got four days off. I don’t need to decide yet, so I’m taking my time with it," Shanahan said on Friday. "Also, I wouldn’t want to do that with all the guys out of the building. I’d like the whole team in here, too, when I decide that.”

When Shanahan was asked what will go into the decision, he answered, "Just who we think gives us the best chance to win versus the Giants."

Mullens made his NFL debut Thursday night, throwing for 262 yards and three touchdowns in a 34-3 rout of the Raiders at Levi's Stadium. He completed 16 of 22 passes with no interceptions for a 151.9 rating -- the best performance in an NFL debut among quarterbacks with 16 or more pass attempts in league history.

Mullens, who signed with the 49ers in 2017 as an undrafted rookie from Southern Miss, got the start against the Raiders because Beathard wasn't fully recovered from right wrist and thumb injuries from the team's 18-15 loss to the Arizona Cardinals on Sunday.

Beathard has 10 NFL starts in his first two seasons. The 49ers are 1-9 in those games. His one victory came last season against the Giants.

Beathard, a third-round 2017 draft pick from Iowa, has completed 57.3 percent of his passes with 12 touchdowns and 13 interceptions in his career.