Former Latics boss Paul Jewell has quit after just over a month in his role with League One club Oldham.
Former Wigan and Bradford boss Jewell, 53, was appointed as Latics manager Richie Wellens' assistant at the end of November.
"Oldham Athletic can confirm that Paul Jewell has resigned from his role as assistant manager," the club announced on their official website.
"The club and manager Richie Wellens would like to thank him for his contributions during his time at SportsDirect.com Park."
Jewell, who guided both Wigan and Bradford to promotion to the Premier League, had been out of management since 2012, when he left Ipswich by mutual consent, before taking on the role at Oldham.
Wellens was appointed Latics boss in September following the sacking of John Sheridan and initially steered them away from relegation trouble.
However, they have slipped back down to 20th in the table after failing to win any of their last five league matches.