Former Bradford midfielder Kerr had his contract terminated last week, and played for the Seadogs on Saturday after joining on a free transfer.
Meanwhile Gary Bradshaw ended his loan spell at the McCain Stadium early to return to Hull and discuss his future. Peter Taylor announced that his contract is being ended becuase "he isn't enjoying his football at the minute."
Elsewhere, ex-Tiger Matt Bloomer is being offered a permanent contract at Lincoln after playing on non-contract terms since being released by City.