Perriman probably has more upside than Anderson. Perriman can do a lot of the deep things Anderson can do. And he's bigger. He played like a stud in the last few games of the season. He has more downside, too, but on a 1-year deal, there's little risk.
In a normal offseason, I would be fine making this swap. This offseason, I would prefer the continuity with Robby Anderson staying. But I'm fine with this swap.
This is kind of like Fant for Beachum. Fant has a wider range of outcomes than Beachum. If you tell me one is a Pro Bowler this year, I would say Fant. If you asked me if Perriman or Anderson had a better chance to make the Pro Bowl, I would say Perriman. But both can also fail.
It seems like Douglas is doing everything he can to keep 2021 as clean as possible on the books.