Goalkeeper Kelle Roos joined Derby County from then-National League side Nuneaton Town in January 2014 following a successful trial with the club.
The Dutch shot-stopper had been tracked by numerous other Championship sides, as well as a number of Premier League teams, including Liverpool, who Roos trained with for a short period prior to linking up with the Rams.
Viewed as one for the future upon his arrival, Roos featured for Derby’s Under 21 side for the second half of the 2013/14 campaign.
After the departure of second-choice shot-stopper Adam Legzdins in the summer of 2014, Roos stepped up to be first-choice custodian Lee Grant’s understudy for the 2014/15 season.
He made five appearances in total during the season – twice in the Capital One Cup and three times in the FA Cup – and kept three clean sheets, highlighting his exciting potential.
After signing a new two-year contract with Derby at the beginning of the 2015/16 season, Roos had a brief loan spell with Rotherham United in the Championship, but after returning to Derby, the shot-stopper headed out to AFC Wimbledon in League 2 for the second half of the season, where he helped the Dons secure promotion to League 1 via the play-offs.
At the start of the 2016/17 season he joined Bristol Rovers on loan spent the first half of the campaign in the South West, making 23 appearances for Rovers before returning to Derby.
Roos began his career in his native homeland at PSV Eindhoven and was a Dutch youth international.
Injuries halted his progress and he also had spells with Dutch top-flight clubs Willem II Tilburg and NEC Nijmegen before moving to England in November 2013.
He impressed in Nuneaton’s first-team and his fine form – with three clean sheets in his first three games - quickly caught the watching eyes of sides further up the football pyramid, with Derby moving fast to secure his services.