Patriots third-string quarterback Jacoby Brissett is in a challenging position because his opportunities are virtually out of his control.

That’s why tonight’s preseason opener against the Jacksonville Jaguars — and the remainder of the exhibition schedule — is integral to Brissett’s development. As long as Tom Brady and primary backup Jimmy Garoppolo remain healthy this season, the four-game preseason slate could be the only time Brissett even gets to wear a gameday uniform.

“Go out there and keep getting better, be ready whenever my chance is called,” Brissett said of his preseason objectives. “Last year is a testament to that. You never know when the opportunity is going to come. You’ve just got to be ready when it comes.”

Brissett has completed 68.0 percent of his passes with three interceptions in team drills during training camp. He got reps only in two third-string periods during the pair of full-contact practices against the Jaguars this week.

It’s impossible to fully gauge Brissett’s development in his second season as he has had few chances to run with the starters. He looks better and doesn’t have nearly as many egregious misses as he did during his rookie training camp, but the best way to assess a quarterback is alongside the highest level of talent.

But Brady doesn’t give up his reps and Garoppolo also needs to develop, so it’s not as if the Patriots can be charitable with Brissett’s reps, especially with CBA-mandated restrictions on practice time.