The 20-year-old midfielder, who joined Rovers from Preston last July, made 21 appearances last term before a cruciate injury ended his season.
Manager John Ward told the club website: "Seanan's signature is another important piece of the jigsaw in building the team.
"Although it is going to be a while before he is back fit, he is still an integral part of the squad, and he could still play a big part this season.
"He has a bright future, and before his injury he showed us what he is capable of. He will be pushing to get back in and around the first team as soon as possible.
"We think it is vital to look after players who pick up injuries while playing for us, and this is an important message to the rest of the team."