Shackleton has missed Leeds’ pre-season tour of Australia in order to push through his loan switch.
He follows teenage centre-back and England Under-21 international Cresswell to The Den where he will work under Gary Rowett.
South London Press report Shackleton is due for a medical with his loan move set to be all tied up this week.
Unlike Cresswell’s straight loan deal, Shackleton’s switch could be made permanent next summer in a similar situation to Tyler Roberts who joined fellow London side Queens Park Rangers on loan earlier this window.
Shackleton’s Leeds deal expires in 2024 and has racked up 78 appearances across all competitions for his boyhood club since joining United at the age of seven.
Check out the latest Premier League transfer speculation below...
1. Pepe in demand
Everton and West Ham United have reportedly joined Sevilla in the race to sign Arsenal winger Nicolas Pepe, who will be sold this summer. (Fichajes)
2. Fulham move for Cornet
Fulham have made their move to sign Burnley winger Maxwel Cornet amid rival interest from Everton. (Daily Mail)
3. Toon ready Mara approach
Newcastle United are ready to make ‘contact’ to sign Girondins de Bordeaux forward Sekou Mara. The ex-PSG player is valued at around £12.7m. (Loïc Tanzi)
4. QPR want Richards
QPR are ‘looking to complete a deal’ for Brighton youngster Taylor Richards. (West London Sport)