Manager John Sheridan bolstered his attacking options with the loan signing of striker Eoin Doyle from Preston North End.
The 29-year-old has joined the club until January 1.
Doyle started his career in Ireland with spells at Shellbourne, Shamrock Rovers and Sligo Rovers.
He made the move to Hibernian in 2011 where he netted 11 goals in a two-year spell.
Chesterfield secured the signing of Doyle in 2013 and he helped them to the League Two title in his debut season and finished the club's top goalscorer.
The following season, Doyle's impressive start with Chesterfield, scoring 25 goals, earned him a move to Championship side Cardiff City for an undisclosed fee.
Following five goals in 16 games, Doyle joined Preston North End on loan before making his transfer permanent at the start of the 2016/17 season.
The striker scored against Oldham Athletic in the second round of the EFL Cup last season.
Doyle later joined Portsmouth on loan at the end of last season and helped them win Sky Bet League Two.
The Irishman will wear the number 13 shirt during his stay with the club.