The person on the 49ers with the most to prove in 2021 isn't a player.
He is defensive coordinator DeMeco Ryans.
Of course, lots of players have things to prove as well. Jimmy Garoppolo will play to prove he's still a franchise quarterback, Trey Lance will play to prove he's ready to replace Garoppolo and roughly half the team will play to prove they can stay healthy for a full season.
But if the 49ers want to make a serious run at a Super Bowl in 2021, they'll need their rookie defensive coordinator to coach like a veteran. Because the roster is excellent and it improved this offseason. The only major loss was former defensive coordinator Robert Saleh, who became the head coach of the New York Jets.
Saleh was the 49ers secret weapon. He routinely outcoached the best offensive minds in the NFL, because his game plans were masterful and his in-game adjustments were even better.
But Saleh wasn't always so great. When he first came to the 49ers, he never had been a coordinator before, and it showed. He was a system coach -- he used Pete Carroll's defensive system. And the 49ers lost certain games because Saleh couldn't adjust on the fly.
Saleh evolved and improved rapidly. And Ryans might do the same. But if Saleh had a learning curve and struggled at first, won't Ryans as well? How many games will the 49ers win in 2021 specifically because of an adjustment Ryans made? How many games will the 49ers lose because Ryans failed to adjust?
The 49ers could afford to let Saleh learn on the job, because they were rebuilding when they hired him. They're not rebuilding anymore. They're in win-now mode. They need Ryans to be good.
Because they could have hired someone with experience to replace Saleh, someone such as Raheem Morris, who has tons of experience and was available. The Rams chose to hire him to replace their defensive coordinator, and the 49ers chose to promote Ryans.
Let's see if the 49ers made the right choice.