Toffees owner Farhad Moshiri was tied into a period of exclusivity with the troubled US investment group until May 31.
The Irishman deputised ably for Alisson Becker at Liverpool last season.
Saracens were narrowly beaten by Northampton to bring Farrell’s time at the club to an end
Real Madrid battle Borussia Dortmund at Wembley Stadium, with England’s Jude Bellingham aiming for his first Uefa Champions League title