From the video

A.J. Brown at this point, where I was trying to go through and trade for him, seeing that he had 10 targets last week... He doesn't look right. He's not able to generate separation. He looks slow. He doesn't look like the young, big, explosive playmaker that he was early in his NFL career. He looks like he's too big... The dude looks like he could lose 15 lb... he came back from the high ankle sprain. These were his first two games. He's going to get 10 days to rest. Maybe he does get better as time goes on. But, he's definitely not nearly as good as I was initially thinking that he was.
STACKED’s take
Post-injury A.J. Brown looks slow, can't separate; source lowering rankings.
A.J. Brown is not performing as expected despite 10 targets last week. Source attempted to trade for him before this game, viewing him as having higher ceiling potential than Jameson Williams, but after watching his performance, concluded he doesn't look right: he's unable to generate separation, looks slow, and doesn't resemble his typical elite form. Post-high ankle sprain performance concerns; appears too heavy at current weight and lacks the explosiveness of early career. Source notes he could lose 15 lb to regain speed. Despite these concerns, source still plans to start him going forward, attributing recent struggles to early games back from injury with 10 days rest potentially helping. Source is lowering A.J. Brown in rankings after reconsidering initial optimism.
A.J. BrownWR · NEPlayer page — value, ADP, projections, and every insight