FOXBOROUGH, Mass. — When it comes to undrafted players, the New England Patriots are an equal opportunity employer.

This is the 14th consecutive year, tied for the third-longest such streak in the NFL, they have opened the season with undrafted rookies on the roster. Tight end Jacob Hollister, tackle Cole Croston, linebacker Harvey Langi and defensive tackle Adam Butler all made the 53.

Of course, there’s a caveat, delivered by none other than coach Bill Belichick.

On Sunday, Belichick cautioned those making their first NFL roster against complacency.

“Well, the reality of it is this is the National Football League and there are plenty of guys that are going to be on rosters today, tomorrow and Week 1 that won’t be on them in Week 3 or Week 4,” Belichick said. “You keep your job by earning your job on a day-to-day basis. I think that’s one of the things sometimes that players, younger players especially who don’t have a lot of experience in the league, can make a poor judgment on.

“It’s a good moment, but it’s a castle in the sand. It could be gone very, very quickly. I hope none of our players, young players, guys who this is the first time they’ve been on this team, take that attitude. I think that would be a big mistake on their part.”

To some, the inclusion of Wyoming’s Hollister on the roster was a bit of a surprise.

“It was just craziness,” Hollister said of learning he had made the team. “Really excited. Just really excited to work my butt off with my teammates. It’s such a blessing to be a part of this organization. So I’m really proud and really happy.”

But it was also bittersweet. His twin brother, wide receiver Cody Hollister of Arkansas, was cut by the Patriots on Saturday.

“Yeah, a little bit,” Jacoby Hollister said. “But we both came into it knowing that’s part of it and this is a business at the end of the day.”

The rookies know their job status can change at any time, like those castles in the sand.

“Absolutely,” Croston said. “By no means am I guaranteed a spot at this point. I’m just taking it one day at a time. I’m just going to do my best every day I’m in the building.”

Croston, whose father Dave played one NFL season for Green Bay in 1988, and started for three seasons at Iowa, is accustomed to job uncertainty. He was a walk-on at Iowa before earning All-Big Ten honors as a senior.

“By no means am I guaranteed a spot at this point,” Croston said. “My sense of urgency, honest, has been high this entire time. I had been a walk-on and I had been undrafted and I was out trying to prove myself, and I don’t think it’s changed up to this point.

“The funny thing is, in the Iowa meeting rooms we always heard a lot of ‘do your job’ and that’s the same thing around here. That’s prepared me for this level because coach Belichick says those things every single day, and Brian (Ferentz, Iowa’s offensive coordinator) instilled it in me at the collegiate level, so it’s helped me a lot.”