he couldn't be guaranteed game time in 1st team Haggarty and Rourke both better options, Thommo is rather like Wingy in his play and even he can't get a game in the first team.
If he can get a good season in at Rochdale and stay injury free I'm sure he'll be retained for next season.
He has been released from his contract, not sent out on loan. Therefore he will be on the open market when his contract expires with the Hornets at the end of the season.