Wes Welker may not be the only important pass catcher Tom Brady is missing when the Patriots season begins in September. His biggest one may be absent as well.

According to multiple sources familiar with the situation, tight end Rob Gronkowski has been battling a stubborn infection in the area around where a second metal plate was installed to repair his broken left forearm and his readiness for the season is in jeopardy.

Gronkowski is nearing the end of a six-week cycle of antibiotic treatments administered under the auspices of Massachusetts General Hospital, but it is not yet assured the infection has been completely eradicated.

Doctors treating Gronkowski will have to go back into the arm again to remove the plate and install a new one, but if they find more infected tissue, they would be unable to install the plate at that time. That would require another surgical procedure after the tissue around the injury is clear of infection and, sources confirmed, that would not give Gronkowski the required 10 weeks healing time to be ready for the season opener in September.

Gronkowski, agent Drew Rosenhaus, team officials, both team physicians and outside consultants are expected to meet within a week to make a determination of what step will be taken next and how quickly to move. All are hopeful the pesky infection has been cured but they cannot be sure until the surgery to remove the old plate and the process to replace it begins.

There are several ways the tissue can be tested, medical sources explained. There is a procedure involving freezing part of the tissue, there is a biopsy and a test that can be done during the surgery to replace the plate.

If the infection has cleared, a new plate would be installed and Gronkowski would have sufficient time to be prepared to undertake normal football activities by the time the season begins.

Gronkowski originally broke the forearm during Week 11 against Indianapolis while blocking during an extra point late in the game. Following the first surgery, he was out five weeks, but played in a limited capacity in the final regular-season game against Miami, then after a bye week, played in the AFC divisional playoff win against Houston.

He didn’t last the first quarter, sustaining a new break just above where the original plate had been installed by team physician Dr. Tom Gill. He then had a third surgery in February specifically to treat the infection and has been on antibiotics ever since.

That new break came despite Gronkowski having been outfitted with a protective cast made of kevlar, the same material worn in bulletproof vests. It was made of the same material used in similar protective casts worn by Rodney Harrison and Mike Vrabel without incident.

While Dr. Gill performed the first surgery, he did not perform the second.

Gronkowski made the rounds on ESPN this past week and did not let on to any issues with a persistent infection or discuss any upcoming surgery.

“The arm is feeling way better than it was during the playoffs, and in the regular season when I broke it,” Gronk said on the “Mike and Mike” morning show. “Right now, I’m rehabbing, getting the muscle stronger around it. You want to get everything activated, re-activated, because it shuts down for a little bit when it’s healing . . . when my trainers give me the good-to-go, hopefully in the next couple weeks, as soon as possible, I can get rolling again . . . doing what I love doing, catching some balls.”

So the bottom line is there’s a way to go before the all-world tight end is ready to play.