The Saints continue to scour the European market to bolster their squad and it is being claimed that representatives from the club were present to watch the 24-year-old Turkey international in action.
Malli didn’t disappoint as he scored a penalty and created two goals in his side’s 4-2 German Bundesliga win against Freiburg on November 19.
He has been at Mainz since 2011 having joined from rivals Borussia Monchengladbach and has spent his career to date in Germany.
However, if Malli continues to impress, the Saints could look to lure him to the Premier League at some point in the future.
A fan who was airlifted to hospital during Chesterfield's 3-1 defeat to Lincoln is responding well to treatment, the Spireites have said.