SANTA CLARA, Calif. — Matt Hasselbeck is one of the poster boys for success when it comes to backup quarterbacks changing teams and becoming effective starters in the NFL.

After throwing just 29 passes in his first three seasons as Brett Favre’s backup in Green Bay, Hasselbeck spent most of the next 10 years as the starter in Seattle, where he made six trips to the playoffs, one Super Bowl and three Pro Bowls.

Jimmy Garoppolo has backed up the best in Tom Brady, but others also had the opportunity – such as Matt Cassel, Ryan Mallett and Brian Hoyer – and never starred as starters. Associated Press/Rick Scuteri

For every success like Hasselbeck or Mark Brunell, there are probably even more busts such as Brock Osweiler, Kevin Kolb and Matt Flynn.

With backups such as Jimmy Garoppolo, Mike Glennon, A.J. McCarron and Colt McCoy possibly on the move this offseason, the task for talent evaluators will be figuring out which group best fits each quarterback.

“One of the things that helped me immensely was the fact that I was Brett Favre’s backup for three years,” Hasselbeck said. “I really became a better player by playing with him every single day. It’s like playing golf with Jordan Spieth every day. You’re just going to get better by osmosis.”

That was a similar pattern that Brunell followed. After two years as Favre’s backup, Brunell was traded to Jacksonville, where he made three Pro Bowls and four playoff appearances in eight seasons as the starter.

Hasselbeck believes Garoppolo is in that same mold if a quarterback-needy team tries to trade for him this offseason, even though he has started just two games in his first three seasons as Tom Brady’s backup in New England.

“If I’m trying to get over the hump and find a guy who’s going to be the leader of my offensive huddle, you really can’t go wrong with how Tom Brady does things. That’s what Garoppolo thinks is normal,” Hasselbeck said. “When I see him play, he almost looks like Tom Brady with his mannerisms. At the end of the day you have to evaluate how did this guy take advantage of his opportunity or not take advantage of his opportunities? He certainly has.”

But that’s no guarantee of success, evidenced by the lack of strong resumes for Matt Cassel, Ryan Mallett and Brian Hoyer after stints as Brady’s backup.

It’s not just New England passers who haven’t been able to make the transition from second string to star.

Osweiler spent four years as Peyton Manning’s backup in Denver and helped the Broncos earn the top seed in the AFC in 2015 on the way to a Super Bowl title when he got the chance to start. That led to Houston giving Osweiler $37 million in guaranteed money last offseason, only to have him lose the starting job late in the schedule to Tom Savage. The Texans are on the hook for one more year of guaranteed money for Osweiler, but could be in the market for another starter or go with Savage next season despite the investment.

Osweiler is far from the only quarterback who was a big acquisition after serving behind a star. Flynn was one of the top quarterbacks to change teams in 2012 when he got a $26 million, three-year contract with Seattle based heavily on a six-touchdown performance in the 2011 finale for Green Bay.

Flynn was beaten out for the starting job by rookie Russell Wilson in 2012, then was traded the next offseason to Oakland, where he was beaten out again for the starting job by Terrelle Pryor, who has gone on to have more success as a pass catcher than a thrower.

After starting seven games in four seasons as a backup in Philadelphia to Donovan McNabb and Michael Vick, Kolb was dealt to Arizona for cornerback Dominique Rodgers-Cromartie and a second-round pick. Kolb got a $63 million contract and started 14 games in his first two years with the Cardinals before being released.

“The less tape, the harder it is,” 49ers Coach Kyle Shanahan said. “So you have to go off what you have. If there’s not a lot of tape in pros, you study everything in preseason, you study everything they’ve done in college, you study everything that’s available.”

Hasselbeck believes his success on a new team was aided by familiarity with Seattle Coach Mike Holmgren, who was the coach in Green Bay when Hasselbeck signed with the team in 1998.

It also helped that no one viewed him as the potential savior in Seattle like people would if Garoppolo changed teams.

“Mike thought I had potential to be that guy, but there was no one else who thought that,” Hasselbeck said. “They were like, ‘Who is this guy?’ I didn’t get the recognition that Jimmy Garoppolo has. There would be a lot of fanfare if a team acquired Jimmy Garoppolo.”