From the video

Video: Week 8 Fantasy Football WR Rankings (Top 43)
AJ Brown has not been seen at practice. This is a knee injury that popped up... Phil Perry, who does a great job covering the Patriots, called the concern for him a nine out of 10... I'm expecting him not to play here... degenerative knee condition... he's just not coming back to the ball uh nearly the same... not nearly as fast as he did before... the change of direction like you know turning his body to to you know come come to the ball.
Mentioned at 31:06 – 32:24Captured by STACKED 6 hr after posting

STACKED’s take

Negative signalInjury

Likely out with degenerative knee; 9/10 concern level; noticeably slower on ball adjustments.

AJ Brown has not been seen at practice with a knee injury that has plagued him for years; Phil Perry (Patriots coverage expert) rated concern level at 9 out of 10. Kyler Gordon expects Brown not to play and notes he's out for the next couple weeks. Beyond the immediate absence, Gordon notes a degenerative knee condition affecting Brown's on-field performance: he's not coming back to the ball the same way, struggles with change of direction and turning his body to track imperfectly placed passes, and is noticeably slower than before. This decline in ability to adjust to the ball is the most noticeable fall-off on tape.

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