New England Patriots coach Bill Belichick refused to comment on the absence of star quarterback Tom Brady from the team's voluntary pre-season training camp on Tuesday amid reports of simmering tension between the two men.
Five-time Super Bowl champion Brady has elected to skip the Patriots' organised team activities, or "OTAs", this year after attending the non-mandatory training camp every year since 2011.
Brady's decision has stoked renewed speculation of a strained relationship between the quarterback and Belichick following reports last season of discord within the Patriots camp.
Belichick however declined to comment on Brady's absence on Tuesday when quizzed about the quarterback's decision to miss OTAs this year.
"I'm not going to talk about the people who aren't here," Belichick said.
"Guys that are here are improving, they're working hard and those are the guys we're going to focus on."
Belichick was similarly taciturn when asked about star tight end Rob Gronkowski. Gronkowski has also opted to skip the voluntary training camp.
"I'm focused on the guys that are here and those are the guys that we're working with in this OTAs process," he said. "Those are the guys who I'm concentrating on."
While attendance at OTAs are optional, Belichick made it clear however how important he views the voluntary camp.
"For everybody to improve every day, every opportunity we get," Belichick said.
"We're working a lot of people so meetings, walkthroughs, film sessions, individual periods, team periods. We've got a lot of people to get reps to. We all learn from every play and that's the stage that we're in right now."
Brady and Gronkowski's NFL futures have both been the subject of debate since the Patriots were beaten in February's Super Bowl in Minneapolis.
Brady, who will be 41 when the 2018 season kicks off in September, indicated last month that he plans to play on.
Uncertainty had also surrounded Gronkowski, who had indicated he was mulling retirement after the Super Bowl loss to the Philadelphia Eagles.
The 28-year-old later confirmed in April he planned to play next season.