Cassidy, 19, scored five goals in 10 appearances during a temporary spell at Prenton Park last season.
The Wales Under-21 international, who is yet to make a first team appearance for Wolves, strengthens Ronnie Moore's striking options following Ben Burgess' retirement.
Manager Moore told the club's official website: "Everybody knows I was impressed by Jake last season so I'm really pleased we've been able to bring him back for the first half of the season. The fact that he was able to finish up as our joint top scorer after only playing 10 times shows how well he did.
"He's got a great eye for goal and a fantastic work ethic. He's keen to learn and wants to do well and I think he's got a really bright future ahead of him."
Cassidy has been given permission to appear in cup competitions and could make his first competitive appearance of the season in the Capital One Cup match away at Chesterfield on August 14.
