ORCHARD PARK, N.Y. (AP) — Buffalo Bills star receiver Stefon Diggs is not present for the start of the team’s mandatory minicamp, coach Sean McDermott said before practice opened on Tuesday.

“I’m very concerned,” is all McDermott would say regarding the absence of the team’s top receiver. Diggs had previously skipped the team’s voluntary spring sessions and workouts.

In clarifying McDermott’s comments, the Bills released a statement saying Diggs was at their facility on Monday and Tuesday morning, and left before practice opened.

The development comes as a surprise after general manager Brandon Beane said last week he expected all 90 players — including Diggs — to be in attendance this week.

An email sent to Diggs’ agent Adisa Bakari was not immediately returned.

Diggs has not commented publicly regarding his reasons for staying away, but has posted various notes on social media over the past few months.

In March, Diggs briefly unfollowed the Bills on Twitter, though the team is once again listed among the 593 accounts he follows, a list that includes many of his teammates.

Diggs is entering his fourth season in Buffalo, and last summer was rewarded with a four-year, $96 million contract that kicks in this season.

Since being acquired in a trade with Minnesota in March 2020, the 29-year-old has been one of the NFL’s most productive receivers by combining for 365 catches for 4,189 yards and 29 touchdowns — one fewer than he had in Minnesota — in his three seasons in Buffalo.

Diggs was particularly upset over how the Bills season ended with a dud in a 27-10 loss to Cincinnati in the divisional round of the playoffs in January.

It was an outing in which Diggs was caught by TV cameras making animated raised-arm gestures at quarterback Josh Allen on the sideline.

His frustrations spilled over afterward, when he immediately bolted from the locker room before McDermott addressed the team, leading to teammate Isaiah McKenzie chasing down Diggs and convincing him to return.

A day later, Diggs avoided reporters and instead shared his disappointment by posting three messages on his Twitter account.

He opened with, “Want me to be okay with losing? Nah,” and followed it up by writing, “Want me to be okay with our level of play when it’s not up to the standard? Nah.” Diggs wrote.