Paul Simpson, First Team Coach at Derby County enthused that; "he looks like he could be a good keeper" and, with two caps for the Netherlands at U-15 level as well as U-16 and U-17 representation, Kelle Roos came to English football with a strong reputation.
Tall, dominant and a powerful kicker, he had initially joined PSV at the age of 13 after playing for three separate clubs in Nijmegen. He conceded just six goals in nine Conference matches with Nuneaton Town, his five clean sheets including one on his début against Chester City.
Another clean sheet marked his first start with Derby County, five cup ties proving the extent of his experience before he was sent out on various loan spells.
Roos conceded ten goals for bottom of the table Championship side Rotherham United, but enjoyed far more success with AFC Wimbledon, where he played against Rovers at The Mem in March 2016 and at Wembley two months later, as his side defeated Plymouth Argyle 2-0 in the play off final to join Rovers in promotion to League One.
Kelle joined Rovers, on a season long loan, on 24th August 2016 and made his debut three days later, in a League One match against Swindon Town. However that match was abandoned after an hour, due to a waterlogged pitch, with the score at 0-0.