49ers: Full Position Breakdown and Depth-Chart Analysis at Quarterback

The San Francisco 49ers have a quarterback competition.

Not a starting quarterback competition. A backup quarterback competition. The exciting kind.

Colin Kaepernick’s starting job is secure even though he has regressed each season he has been the 49ers’ starting quarterback. His backups are Blaine Gabbert, a former first-round pick and one of the biggest busts in league history, and an undrafted free-agent rookie named Dylan Thompson who may or may not make the final roster.

The Niners may or may not keep more than one backup quarterback. If they keep only one, Gabbert probably will be the one they keep. But don’t overlook Thompson. He’s a sleeper.

Here is an in-depth look at the 49ers’ current quarterback depth chart.

Starter: Colin Kaepernick

If Kaepernick never improves, he’s still a dangerous runner and an exceptional rollout play-action passer who’s good enough to take the Niners to the playoffs next season. He gives them a chance.

The Niners would have no chance if Kaepernick suffers a season-ending injury. They’d be finished.

I know what you’re probably saying: “Any team would be finished if it lost its starting quarterback.” I hear you. Tell that to the Arizona Cardinals. They lost starting quarterback Carson Palmer Week 10 last season against the St. Louis Rams and still made the playoffs.

A season-ending injury to the quarterback doesn’t have to sink a team, especially a run-first team like the Niners. A decent backup quarterback can keep the team afloat.

If only Gabbert were a decent backup.

Backup: Blaine Gabbert

The Oakland Raiders have a good head coach mostly because of Blaine Gabbert. Let me explain.

From 2003 to 2010, Jack Del Rio’s coaching record with the Jacksonville Jaguars was 65-63—a good record for such a bad franchise. Two-time Super Bowl champion Tom Coughlin—one of the best coaches in the NFL—didn’t do much better when he coached the Jaguars from 1995 to 2002. His record was 68-60.

Del Rio had a track record of success before Jacksonville drafted Gabbert in 2011. But Gabbert lost eight of his first 11 starts his rookie season, and the Jaguars fired Del Rio Week 12.

Del Rio wasn’t the Jaguars’ problem—Gabbert was. The NFL is a quarterback-driven league, and Gabbert went 5-22 as Jacksonville’s starting quarterback before the Jags got rid of him in 2014. He would have gotten any coach fired.

The Jaguars should have gotten rid of Gabbert earlier and kept Del Rio. Oops. Now the Raiders have Del Rio.

And the Niners have Gabbert—for some reason they signed him in 2014. Maybe they thought he’d flourish after a change of scenery. He hasn’t so far. During last year's preseason, Gabbert completed just 46.8 percent of his passes.

But he made the team because he was the best backup quarterback on the roster. He won the job by default.

This year, he might have legitimate competition.

Third String: Dylan Thompson

Dylan Thompson started only one season in college. That’s probably the reason no team drafted him this year. Teams usually prefer quarterbacks who started three or four years in college.

Despite Thompson’s lack of experience, he produced at the University of South Carolina. Last season, he led the SEC in passing yards, and he threw 26 touchdowns passes—he must have been doing something right.

At Thursday’s OTA, I watched him work during 11-on-11 team drills. He didn’t do anything spectacular, such as throw a 60-yard touchdown pass, but he did something subtle and difficult. On one play he dropped back, looked left, reset his feet, looked forward and completed a pass to the No. 2 receiver in his progression, all in rhythm.

Rookies rarely go through progressions in the pocket that calmly and gracefully. They typically rush because they’re overwhelmed by the speed of the NFL game. Young quarterbacks need time to adjust. Gabbert STILL is adjusting. He may never adjust.

Thompson may win the backup quarterback job if he continues to play with poise in the pocket.

Follow @grantcohn.