Really it is. They were going to have to trade for a backup anyhow and he was never going to get that money on the open market while recovering from his injury… he gets several million more than he would have if they simply cut him.. and they likely get a comp pick from itSmart deal for the 49ers.
He also has total control of his future with a no franchise and no trade clause… he can rehab in peace, play in a familiar system if called on, and be a lucrative free agent next offseason