Keogh, 32, re-joined the club for a third time in February 2018 and was appointed captain ahead of the 2018/19 season.
He will now take charge of team affairs following the departure of Dave Wild to Matlock, while the club searches for his permanent successor.
The attacking midfielder has made 206 appearances for Mossley.
His first game in temporary charge will come at Dunston on Saturday, the first of eight away games in their next nine.
Keep up-to-date with our exclusive email newsletters.
Digital advertising by Minute Media
© Pitch Hero Ltd 2008-2020
Pitch Hero Ltd Registered in ENGLAND | WF3 1DR | Company Number - 636 1033