Raheem Mostert officially wants OUT of SF after helping lead the 49ers to a Super Bowl ... the RB's agent says contract talks with the team have failed -- and now, he's demanding a trade.
The 28-year-old -- who rushed for a staggering 220 yards and 4 TDs in the NFC Championship Game win over the Packers -- has been angling for a raise since the season's end.
But, Mostert's agent said Wednesday the Niners won't budge ... so Raheem wants to play elsewhere now.
"After months of unproductive talks with the 49ers about fairly adjusting Raheem Mostert's contract (which paid him for special teams) we have requested a trade," agent Brett Tessler said.