Darren Bent insisted he had to leave Aston Villa after too many "slaps in the face".
Brighton defender Greg Halford has agreed to extend his loan deal from Nottingham Forest until the New Year.
Striker Lewis Guy has secured his release from St Mirren.
Cumbria-born Guy had been told he was free to find a new club and had been training with Carlisle before reaching agreement with Saints to end his contract a year before it was due to expire.
A club statement read: "It has been confirmed this morning that Lewis Guy has cancelled his contract with St Mirren Football Club by mutual consent."
The 27-year-old joined St Mirren a year ago from MK Dons and hit six goals in 35 appearances.
His final appearance, in a goalless draw with Aberdeen in the penultimate match of the season, saw him substituted 16 minutes after coming on, following an exchange of words with assistant manager Tommy Craig.