Kelle Roos

In the Netherlands

Roos began his career at amateur Dutch clubs VV Toxandria, VV Trekvogels, Juliana '31 and Quick 1888 before moving to PSV Eindhoven. He then moved to Willem II, where injuries hampered his progress, before moving to N.E.C.

Move to England

At the start of the 2013–14 season, Roos had a trial at English Championship club Birmingham City and then at Football League One side Bristol City. He competed with Elliot Parish for the chance to win a permanent contract, with manager Sean O'Driscoll then signing Parish permanently. O'Driscoll wanted to sign Roos and loan him out, but "finance dictates what we can and can't do" and he was thus unable to sign both of them.

Nuneaton Town

Having failed to earn a contract and unable to join a league side as the transfer window had closed, Roos returned to the Netherlands and signed for amateur side RKSV Nuenen. Having received offers from the Netherlands and England, Roos went on to join Conference Premier side Nuneaton Town on 8 November 2013, signing a contract until the end of the season. His debut was delayed by almost two weeks as the club waited to receive international clearance. He played nine league matches, keeping five clean sheets, and also played four cup matches, keeping three clean sheets, not conceding a goal in his first six appearances.

Roos' excellent form drew the attention of Liverpool, with whom he spent a week's trial in early January 2014, as well as Everton, Sunderland and Cardiff City. He also spent time training with Ipswich Town and Bolton Wanderers and was scouted by Crystal Palace, Queens Park Rangers and Bournemouth.

Derby County

On 23 January 2014, Roos moved to Championship side Derby County after impressing during a trial. He signed a two-and-a-half year contract for an undisclosed fee, believed to be around £30,000 plus add-ons, including the requirement that Derby play a pre-season friendly with Nuneaton in the Summer.

After the departure of goalkeeper Adam Legzdins, Roos has been understudy to Lee Grant and as of September 2014, has appeared on the substitutes bench in every match of the 2014–15 season.

He made his professional debut for The Rams on 23 September 2014 in a Football League Cup game at home to Reading. He made several saves and kept a clean sheet as Derby won 2–0.

Rotherham United loan

On 15 July 2015 it was confirmed that Roos would join Rotherham United on a season-long loan deal along with team-mate Farrend Rawson. It was also confirmed that Roos would be ineligible to play against his parent club for the duration of the loan period. However, Roos returned to Derby just six weeks into the loan period after conceding ten goals in his four appearances, leaving Rotherham bottom of the table.

International career

During his time at PSV, Roos played for the Netherlands under-15s, under-16s and under-17s.