The 20-year-old midfielder enjoyed a successful loan spell at Peterborough United before Christmas last season, going on to make seven appearances for West Brom upon his return.
However, Thorne's promising run was cruelly halted by a ruptured anterior cruciate ligament in his right knee, sustained against Everton on January 30, which ruled him out for the rest of the campaign.
"I had a spell last season where I got the chance to show what I can do," he told the club's official website.
"Hopefully, this season I can push on from there.
"I want to give the gaffer an idea of what I am as a player.
"It looks as though there are going to be some very good players on our bench so I know it's going to be difficult.
"For me personally, if there's an opportunity for me to go and play some games, then we'll sit down and have a look at that.
"Hopefully, I'll get the chance to play some football and get back to where I was."
