Swindon Wildcats head coach Steve Lyle has left the club, general manager Steve Nell has told BBC Wiltshire.
Wildcats forward Aaron Nell has been put in charge of the team ahead of the matches against Guildford and Basingstoke this weekend.
"It's a shock to us, everything was fine on Sunday night and things have happened in the week and Steve was not happy," Nell told BBC Wiltshire.
"He's quit, I understand if he is not happy it is the right thing to do."
Lyle, a former Great Britain international, signed for the club at the start of the 2013-14 campaign and became head coach in 2015.