Obviously we don't know what's going on, but if I had to guess, they're looking at bringing Stills in now and getting him up to speed to have a veteran with good experience ready in case Brown or Beasley try to come back but get re-injured or can't go full speed.
Also, like others have said, might be good to get him in next week vs. Miami for some reps. Maybe even an audition for 2021.