He had great separation on Thursday and just missed on two huge plays, scorching veteran CBs. He caught one, but the ball drifted out of bounds and the other was just outside of his reach.
He lit it up in practice on Monday.
"On Monday, he pushed that aside to have his best day of training camp by a substantial margin. Foster was all over the place, making catch after catch during team drills..."
https://www.wkbw.com/sports/bills/joe-b-7-observations-from-2018-buffalo-bills-training-camp-day-14
He has blazing speed and he knows how to get open.