More than £80m has now been spent on Trafford in initial transfer fees.
As part of the deal taking him to Leeds, BBC Sport understands City will retain a 20% sell-on clause and have matching rights – meaning if they match a future offer for Trafford they will get first refusal on him.
Leeds boss Daniel Farke appears willing to pay a premium despite Trafford’s limited opportunities at Manchester City last season, after both Karl Darlow and Illan Meslier left Elland Road this summer.
Lucas Perri and Alex Cairns remain on the books, though Perri lost his place to Darlow in the second half of last season and did not feature in the Premier League after a 4-3 defeat by Newcastle on 7 January.
Leeds are investing in the potential of a young goalkeeper whose highlights have largely come in the Championship with Burnley, where he conceded just 16 goals in 45 appearances.
Trafford has only played 32 top-flight games, but former Clarets boss Scott Parker previously praised his turnaround at Turf Moor before moving to the Etihad.
Praised as “world class” by Parker, Trafford’s 29 clean sheets and 84.47% save ratio were key to Burnley’s promotion back to the Premier League in 2024-25.
Trafford began his career at City and had loan spells with Accrington Stanley and Bolton Wanderers before joining Burnley in 2023.
He made 73 appearances for the Clarets before City activated their buy-back option last summer.