The Patriots will open training camp tomorrow with one of the most complete rosters in Bill Belichick’s 18-year run as coach.

It’s going to be hard enough for late-round draft picks and veteran players without a significant role to fight their way onto the 53-man roster. So is it even possible for an undrafted rookie free agent to make the cut?

Well, if the last 13 seasons are any indication, yes.

The Patriots have carried at least one undrafted rookie free agent on their Week 1 roster for 13 consecutive seasons. That’s tied for the third-longest active streak in the NFL behind only the Chargers (20) and Colts (18).

In the past, the Pats have opted to keep numerous undrafted rookies that have excelled in training camp. For instance, in 2013 they hung onto six players from their undrafted rookie class, the most in the Belichick era. Included in that group were punter Ryan Allen, offensive lineman Josh Kline and wide receiver Kenbrell Thompkins. And last season, running back D.J. Foster and defensive back Jonathan Jones made the cut and remain with the team.

Several of the undrafted overachievers made a quick impact with the Patriots. Randall Gay, who began the streak of undrafteds making the roster in 2004, started nine games that season and had two interceptions for the Super Bowl XXXIX champions. David Andrews started 11 games in 2015 as an unheralded rookie center handling snaps for Tom Brady. Allen has handled the punting duties for every game since 2013.

But the most obvious example of the Patriots finding a star among the ranks of the undrafteds is cornerback Malcolm Butler. Butler was one of two undrafted free agents, along with linebacker Deontae Skinner, to make the 2014 roster out of camp. He played just 184 snaps (17 percent of the total) on defense during the regular season, which was dead last among Pats cornerbacks. Butler didn’t see the field on defense in the divisional playoff round against the Ravens and only logged 15 snaps in the AFC Championship Game against the Colts.

Then Butler changed the course of NFL history.

He played 18 snaps in Super Bowl XLIX — more than he saw in the entire playoffs to that point — and was in place to make the game-saving interception at the goal line when his pick of Russell Wilson sealed the title for the Patriots.

Butler is living proof that Belichick isn’t too impressed by football pedigree. He will give an opportunity, even on the biggest stage, to players who prove on the practice field they can help the Patriots win, regardless of how they arrived in Foxboro.

For this year’s undrafted rookie free agent class, Butler should be a beacon of what can happen.

The Patriots have a number of intriguing undrafted options who could keep the streak alive. The best bet is BYU linebacker Harvey Langi, to whom the Patriots gave the most money of the 2017 undrafted class. But Northwestern slot receiver Austin Carr and Wyoming tight end Jacob Hollister ought to receive plenty of opportunities to impress the coaching staff.

If there are others who deserve an extra look, you can expect them to get it from the Patriots coaches, who know a thing or two about finding a needle in a haystack full of undrafted free agents.