Stags added to their squad with the impressive acquisition of talented midfielder Jacob Mellis from League One side Bury.
The 26-year-old began his career as a youth team scholar at Sheffield United, before joining Premier League champions Chelsea for £1m in 2007.
He was a member of the Blues' youth team that reached the FA Youth Cup Final under Paul Clement in 2008.
The former England U16s' captain made his Chelsea debut in a Champions League win against MSK Zilina in November 2010.
After a brief loan spell at Southampton, Mellis signed for Barnsley, where he was a consistent performer in the Championship, making over 70 appearances in a two year spell.
In July 2014, the versatile midfielder moved to then-Championship outfit Blackpool, before enjoying spells at Oldham Athletic and Bury in League One.