Portland Trail Blazers restricted free-agent guard Allen Crabbe has signed a four-year, $75 million offer sheet with the Brooklyn Nets, league sources told The Vertical.

The contract includes a fourth-year player option and a 15 percent trade kicker that could escalate the deal to $83 million, sources said.

The deal is a monstrous package for a 24-year-old guard who averaged 10.3 points as a Blazers reserve in his third NBA season.

The Nets plan to make Crabbe a starter, but his role with the Blazers would continue to be as a reserve behind C.J. McCollum.

The Blazers received the signed sheet on Thursday night and will have three full days to match the offer and retain Crabbe – or let him leave for the Nets.

Agent Aaron Mintz of CAA Sports represents two of the Blazers’ restricted free agents – Crabbe and 7-footer Meyers Leonard.

For new Brooklyn general manager Sean Marks, the offer sheet is another bold free agency move. Marks signed Miami’s Tyler Johnson to a four-year, $50 million offer sheet and has $125 million committed to two guards who have started a combined 24 NBA games. Nevertheless, the Nets are devoid of first-round picks in coming years and are trying to be creative in bringing young talent into the organization.

Blazers general manager Neil Olshey drafted Crabbe with the 31st overall pick in the 2013 NBA draft and watched his coach, Terry Stotts, develop him into a rotation player who averaged 26 minutes a game last season. The Blazers had planned to match an offer sheet to keep Crabbe, but it is immediately unclear if that’ll make fiscal sense – even with a rising salary cap.

Crabbe is one of three restricted free agents on the Blazers’ roster, along with Leonard and forward Maurice Harkless.