As Colin Kaepernick’s audition continues for the next three games, there’s one 49ers quarterback no one talks about. Thad Lewis was signed after a year backing up Chip Kelly’s quarterbacks in Philadelphia.

Like fellow 49ers quarterbacks Blaine Gabbert and Christian Ponder, Lewis is on a one-year deal. Unlike those players, Lewis is on injured reserve after tearing his anterior cruciate ligament Aug. 14 in the 49ers’ preseason opener against Houston. Two days later, he had surgery and was placed on season-ending injured reserve.

“I am feeling good,” Lewis said on Tuesday after taking a break from his ongoing rehab. “The main thing is being ready when it counts and that’s going to be April and being able to go into OTAs (off-season practices),” Lewis said. “One thing I learned in this league, you can’t take back reps.”

Lewis knows a lot about the league. Since latching on to the St. Louis Rams in 2010 as a rookie free agent from Duke, Lewis has been with six different teams. What he craves is a chance to get into a second year with the same offense, something that hasn’t happened since his junior to senior year in college.

At Duke, Lewis went from 15 passing touchdowns to 20 his senior year, and from 2,171 yards to 3,330 yards. In the ideal scenario, the 49ers retain coach Chip Kelly and Lewis gets another contract with the 49ers.

“It takes more than just one year to get this offense together,” Lewis said. “In year two, guys actually succeed, in year three? Lights out.”

That’s not how it necessarily worked during Kelly’s three-year stint in Philadelphia. In Kelly’s first season, the Eagles offense threw for 32 touchdowns, 13 interceptions and averaged 6 yards per offensive play. The next year, the Eagles threw for 38 touchdowns, only six interceptions and averaged 6.3 yards per play. Then things collapsed in the “lights out” third year when the Eagles dropped to 23 touchdowns, 18 interceptions and averaged 5.3 yards per play. However, that might have been due to poor personnel decisions by Kelly.

Nevertheless, Lewis’ point is valid, give the gutsy Lewis a third year in the same system and who knows what may happen, it could just be lights out.

Another aspect Lewis has admired this year other than Kelly’s offense, is starter Colin Kaepernick’s resolve to social issues. Keapernick continues to kneel for the national anthem as a protest against racial injustice and police violence in communities of color.

“He was willing to take the heat and whatever came with it, and you have to commend him for that,” said Lewis, an African American who grew up in South Florida. “I don’t think it’s affected his football. You got a guy who can jugged some things and you have to tip your hat off to him.”

What’s impressed Lewis is Kaepernick’s preparation for football and his off-field campaigns.

“He’s knowledgeable about the (social) situation. If you have any questions, he has the answer for you,” Lewis said. “When a guy is prepared like that, he can take the heat and answer any question and have knowledgeable sources to go with it.”

Lewis also hopes to be prepared for spring football, wherever that might be. Just four months after knee reconstruction, Lewis started running this week. Maybe that will convince the 49ers that good health and continuity might be just the ticket for a duel threat quarterback nobody is talking about.

Twitter: @klynch49