FOXBOROUGH, Mass. -- New England Patriots coach Bill Belichick praised quarterback Mac Jones' improvement leading into Sunday's season opener against the Philadelphia Eagles, while leaving open who might serve as his top backup.

"Mac's had a good offseason and has had a really good camp," Belichick said in a video conference Monday morning. "He understands the offense -- how it works, how to get his teammates involved, how to help them be productive. So he's had a really good stretch here; it's been consistent all the way through."

Belichick also told sports radio WEEI that Jones is in "excellent physical condition," has "made a lot of improvement in reads, decision-making and timing," and that he's "looking forward to the season with Mac."

Those were decisive words coming from Belichick, who at the start of training camp noted how every player on the roster -- including Jones -- was competing for a starting role.

As it turned out, Belichick kept just Jones at quarterback on the team's initial 53-man roster last week, waiving his primary competition, Bailey Zappe, and undrafted free agent Malik Cunningham.

The Patriots brought Zappe and Cunningham back on the practice squad a day later, with Belichick explaining his thinking on Zappe publicly for the first time Monday by saying: "All roster decisions are based on what we feel like is best for our football team, so there's a number of things involved there. We're glad to have Bailey, going to continue to work with him, still think he's a good, young developing player."

The Patriots also claimed second-year quarterback Matt Corral on waivers from the Carolina Panthers last Thursday, putting him on their 53-man roster.

While Corral is technically ahead of Zappe on the depth chart by being on the 53-man roster, Belichick said he was unsure whether Corral would be ready for No. 2 duties for the opener.

"He hasn't even been on the field yet, so we'll see," Belichick said before the team's practice Monday afternoon.

"Matt was available; we'll add him to the group and see how it goes. Based on what we saw in Carolina and going back to the college film at Mississippi, he's a player we wanted to work with."

The Patriots have the option of elevating Zappe from the practice squad for Sunday's opener as the No. 2 option, and under the NFL's new rules for third quarterbacks, could make Corral the emergency No. 3 option and not have him count against the 47-man game-day roster limit (or 48 if a team activates at least 8 offensive linemen).