Charlie Dawes and Michael Onovwigun will remain on loan at Matlock Town and Sheffield FC respectively.
Both deals have been extended until January 3 with a 24-hour recall clause inserted in the agreements.
Striker Dawes, signed in the summer after being released by Sheffield Wednesday, has made one senior appearance for Chesterfield, appearing in the JPT tie at Scunthorpe in early September.
Onovwigun has made a couple of appearances as a substitute for the Spireites. The 18-year-old former Brentford midfielder joined Chesterfield in the summer following a spell on trial.