Duo depart

The pair have both featured for the reserves on a regular basis this season and Hartley, a centre-back, made his first-team debut during last season's Championship campaign.

Dowson and Hartley, both 19, will be available for selection on Saturday when the Spirerites take on Brentford.

Chesterfield are currently 10th in League Two and only two points away from the play-offs.