High Quality Content by WIKIPEDIA articles! John Morgan Oster (born 8 December 1978) is an English born Welsh international footballer, who plays as a midfielder for Football League Championship club Doncaster Rovers. Oster progressed through the youth ranks at Grimsby Town before moving on to Premier League Everton. He went on to feature for Sunderland and Barnsley before returning to Grimsby on loan, from there on he has also featured with Leeds United, Burnley, Reading and Crystal Palace.