Sagan Tosu said Friday that manager Yoon Jung-hwan’s contract with the J. League front-running top division club was terminated because of a lack of trust between the South Korean and his players.

No further explanation was given for the firing of the 41-year-old Yoon, leaving more questions than answers. Tosu coach Megumu Yoshida, 41, has been promoted to manager for the remainder of the season. Yoon has already left the club.

Takayuki Nagai, in charge of team development, denied that Yoon’s termination was due to differences in opinion about club tactics or discord with the front office, such as a breakdown in contractual negotiations for next season.

He did, however, suggest that there had been a growing split with Yoon concerning the latter’s methods.

“Attention and care (toward players). There’s no problem with those who are playing, but there are those who aren’t playing. It’s his way of leading (those who aren’t playing),” said Nagai, adding that the club’s front office held talks with Yoon nearly 10 times during the World Cup finals in Brazil, but the sides were unable to resolve their differences.

Nagai said it was a tough decision for Tosu, who currently lead the 18-club division ahead of second-place Urawa Reds and third-place Kawasaki Frontale.

“It was a painful decision. We are in first place, but if we fall apart at the seams when something happens, we wonder if we can maintain our position in first,” Nagai said.

As a midfielder on the South Korean national team, Yoon appeared in the 1996 Atlanta Olympics and the 2002 World Cup co-hosted by South Korea and Japan. He played for Cerezo Osaka and Tosu in the J. League before retiring in 2007.

Yoon took a head coaching job at Tosu before he was appointed manager in 2011, leading the then-J2 club into the top division with his emphasis on player agility.

The club finished in fifth in his first season at the top flight in 2012 but dropped off into 12th the following season, despite reaching the semifinals of the Emperor’s Cup.