The 21-year-old, who was due to spend the whole of the season at the Stadium of Light, has scored seven goals in 17 games in the Championship this season, including two in his last two matches.
Simms, who is a product of Everton’s academy, will officially return on 1 January and will be eligible to face Brighton at Goodison Park on Tuesday.
Everton go into Saturday’s game against Manchester City as the third-lowest scorers in the Premier League, with just 12 goals in 16 games.
They have only had two goals from specialist strikers this season, with Dominic Calvert-Lewin getting one in an injury-hit campaign and Neal Maupay one since his summer arrival from Brighton.
Simms has made one appearance for Everton, in 2021’s draw at Chelsea, and has also been loaned to Hearts and Blackpool.