Image source, Getty Images Image caption, Jacob Widell Zetterstrom has featured 71 times for Derby since joining the Championship side from Swedish side Djurgarden ByAndrew Aloia, BBC Sport, East Midlands and Ed Dawes, BBC Radio Derby Published 21 minutes ago Jacob Widell Zetterstrom is still undergoing tests to try deal with a mystery illness that has kept the Derby County goalkeeper out for much of the past six weeks, with Rams boss John Eustace describing it a "worrying time".