Nick Mullens was not among the 15 quarterbacks invited to the NFL Scouting Combine in 2017.

Only the 49ers invited him to their facility a pre-draft visit.

“That was my only visit, but was in contact with a handful of teams,” Mullens said recently on The 49ers Insider Podcast.

But when he was not one of the 10 quarterbacks to get drafted, other teams called to try to sign him to their 90-man rosters. He already knew 49ers coach Kyle Shanahan and quarterbacks coach Rich Scangarello, so his decision was easy. His original contract with the 49ers included a $2,000 signing bonus.

“I had undrafted opportunities with a handful of team, but Coach Scangarello and Coach Shanahan just provided me with every opportunity for success,” Mullens said. “I chose the 49ers and the 49ers chose me, and it’s been a great run since then.”

Mullens, who spent his entire rookie season on the 49ers’ practice squad, made his NFL debut on Thursday against the Raiders.

He completed 16 of 22 passes for 262 yards and three touchdowns with no interceptions, as he replaced injured C.J. Beathard. The 49ers snapped a six-game losing streak with a 34-3 victory at Levi's Stadium. Mullens’ 151.9 passer rating is the best debut in NFL history among quarterbacks with 16 or more pass attempts.

After a record-setting career at Southern Miss, Mullens was not considered a top draft prospect because of his less than ideal size (6-foot, 7/8 inch) and arm strength.

However, he said he did not spend too much time agonizing over how the draft would impact his football career.

“I guess you could blame it on my size,” Mullens said. “I don’t know, to be honest. I don’t really care. I focus on working and being the best I can be each and every day. And I’ve had that mindset since high school. The only thing that matters is what you do on the field.

“I always thought I’ll get some sort of chance in the NFL, and it was up to me to make that last as long as I can. So that was kind of my mindset going forward, and so far it’s worked out.”