Morgan Whittaker is set to join MLS side Colorado Rapids from Middlesbrough in a $10.7million (£7.9m) deal, talkSPORT understands.With the MLS summer transfer window closing on Wednesday night, Whittaker is primed to complete a club-record move to the US outfit before the deadline.Whittaker is set to leave Middlesbrough after 18 months at the RiversideAccording to reports, the Middlesbrough winger is flying to the US to finalise the move after completing a medical in London on Tuesday.Whittaker joined Boro for a fee of around £7m in January 2025 from Plymouth Argyle.The 25-year-old went on to play an instrumental role for the club last season as the Championship side secured a play-off finish.He registered 14 goals and seven assists in 40 appearances, as Boro’s promotion push initially ended at the semi-final stage after they crashed to a final-four loss to Southampton.However, as a result of the ‘Spygate’ scandal, they were reinstated at Saints’ expense, only to fall to a late 1-0 defeat to Hull in the Championship showpiece at Wembley back in May.Whittaker’s impressive displays have made him a hot property this summer, with West Ham previously showing an interest.talkSPORT previously revealed in July that the Hammers were looking to complete a deal for the forward before the start of the Championship season, having seen star winger Crysencio Summerville depart to join Al Hilal.But Whittaker now looks set to follow in Summerville’s footsteps by securing a move away from English football.Rapids’ big businessWhittaker is now on the brink of joining the Colorado Rapids in a new record transfer for the club.The Rapids’ previous record is $7m (£5.2 m) to sign current star Paxten Aaronson from Eintracht Frankfurt in 2025.Whittaker will no longer be plying his trade under Boro boss Kim HellbergGettyOnce he completes a move, Whittaker will join up with English coach Matt Wells in Colorado.Wells has overseen an attacking overhaul this summer and is now placing an emphasis on wide play, with Whittaker viewed as the main man to spearhead this.With the Rapids set to shell out a landmark fee for the Boro star, they are also doing business in the opposite direction.According to the Athletic, forward Rafa Navarro is set to join St. Louis City in a deal worth $12m (£8.8m).The MLS Western Conference side also sold centre-back Lucas Herrington to Hull this summer for an initial fee of $17m (£13m) plus add-ons that could take the deal past £20m, in a record fee for an Australian player.As well as Whittaker, Israel international forward Sayed Abu Farchi has also completed a move to Colorado for a $6m (£4.4m) fee.Herrington was a high-profile departure from the Colorado Rapids this summer, and has since made his Premier League debut for HullGettyMLS sides are allowed to sign a maximum three designated players – a rule that allows franchises to sign up to three players considered outside their salary cap.And Whittaker’s anticipated arrival will see to become the Rapids’ club second DPs, alongside Aaronson.Colorado have enjoyed a solid season so far, and currently sit seventh in the Western Conference with 31 points after 22 matches.