BOSTON (CBS) — The Patriots placed rookie tight end Devin Asiasi on injured reserve on Tuesday, but nobody is quite sure why.

Asiasi missed Sunday’s game in Buffalo due to personal reasons. He had posted on Instagram on Saturday about the death of a friend.

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The Patriots, of course, did not practice on Monday or Tuesday, so Asiasi didn’t have a chance to suffer an injury on the field. He was not listed on the Patriots’ injury report last week, either, adding to the mystery of Tuesday’s placement on IR.

On Wednesday morning, Belichick was asked about Asiasi’s placement on IR. He said the move was not related to the personal reasons for missing Sunday’s game.

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“It’s separate,” Belichick said. “He’s on injured reserve with an injury, not a personal situation.”

When pressed for more details about why Asiasi hasn’t appeared on injury reports, Belichick reiterated: “I don’t really have anything to add. He wasn’t in Buffalo for personal reasons. He’s on injured reserve because of an injury.”

Asiasi, 23, was drafted out of UCLA by the Patriots in the third round (91st overall) in this year’s draft. He’s played in six games and has yet to catch a pass. He was on the field for 29 snaps in the win vs. the Raiders and 24 snaps in the loss to Denver, but he’s played 10 or fewer snaps in his other three games played. He was a healthy scratch in Week 7 against San Francisco before missing the Week 8 game for personal reasons.

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Unlike in other years, teams can activate an unlimited number of players from IR, and the wait to do so is only three games. So Asiasi will be eligible to return from IR as soon as Week 12 vs. the Cardinals.