FOXBOROUGH – Just as the injury concerns for Mac Jones' back died down, the New England Patriots quarterback is dealing with something else.

Jones will miss Thursday's practice due to an illness, the Patriots announced. The good news for the Patriots is that it appears' Jones' illness is just an upset stomach and not COVID-related, the NFL Network's Tom Pelissero reported.

The NFL made changes to its COVID policy ahead of the 2022 season that lax testing requirements but still force players to miss time if they test positive for the virus. If a player shows any COVID-like symptoms, they must self-report them and test negative before entering the team's facilities. If a player tests positive for COVID-19, they must self-isolate for five days. So, if Jones were to test positive on Thursday, he would miss Sunday's game against the Steelers.

Mac Jones' absence from practice comes four days after he suffered a back injury in the Patriots' season-opening loss to the Dolphins on Sunday. The quarterback missed his press conference after the game in order to have X-rays. Those X-rays reportedly came back negative and it was later revealed that Jones was dealing with back spasms.

Mac Jones was a full participant at Wednesday's practice and said his back is feeling good. He also added he's expected to play in Sunday's game.

“It feels good,” Jones said. “Everything feels good. Just keeping it warm and throwing the football.”

“[I'm] just on the normal treatment plan,” Jones added. “I always like to work with my guy [Patriots athletic trainer] Brian [Dolan] and he does a good job. That’s what we always do. Whatever hurts during the game, just fix it and then play the next week.”

Mac Jones is the only Patriots player on the active roster who's absent from Thursday's practice. Linebacker Ja'Whaun Bentley, who was the only Patriots player on the active roster to miss Wednesday's practice (toe), was back on the field at Thursday's practice.