He is set to undergo further tests as he waits to learn how long he will be out of action. Leeds are expecting the player to be out for a “lengthy period”.
Posting a picture on Twitter from his hospital bed, Dallas said: “Huge thank you for all of the messages I’ve received in the past few days.
“I’ve had amazing support from across the world of football – but particularly from Leeds and Northern Ireland. I’d also like to thank Dr Williams, Dr Sarraf and the medical team at @LUFC.
“The support I’ve received has meant the world to me and my family. Now it’s time to focus on my rehab, I will be back from this stronger than ever.
“In the meantime I’ll be supporting my teams every step of the way.”
Dallas will miss the rest of Leeds’ battle for league survival after being injured in a 50-50 challenge with Jack Grealish in the 4-0 defeat to City at Elland Road. The Whites are two points above 18th-placed Everton and level on points with Burnley in 16th. The Toffees have a game in hand over both of the clubs immediately above them.
He will also be absent for Northern Ireland's international schedule during the summer as they kick off their 2022 Nations League campaign with games against Greece, Cyprus and Kosovo next month.