Sheffield FC have announced that manager Curtis Woodhouse has resigned.
The 32-year-old professional boxer took over the Northern Premier Division One South side in May.
The former Sheffield United and Birmingham player leaves the club in 13th position in the table after a 5-1 home defeat by Belper on Boxing Day.
A club statement said: "Curtis has found it difficult to manage a professional boxing career with the time pressures of football management."
Woodhouse quit full-time football in 2006 to pursue his ring career and won the English light-welterwight title in September.
He has a record of 17 wins and four defeats from 21 fights.