V-League club Dong Tam Long An (DTLA) coach Jose Luis told his players at practice on Wednesday that he was going home to Portugal for medical treatment.
The Portuguese coach said he would need treatment for a few months before he returned to the club, based in the Mekong Delta's Long An Province.
It came as a surprise because he had earlier said he felt fir and healthy after more than a week's rest due to medical ailments.
However, observers speculated that his leaving might have been because of a sudden meeting between him and the club owner Vo Quoc Thang earlier Wednesday.
The club managers have not said that they fired the coach. But his absence for a few months could mean the club would replace him with another coach.
DTLA didn't finish among the top four in the 2009 V-League season. It is now in third place after round four of the 2010 season with six points.
However, the Mekong Delta club took the two latest wins while Luis was taking a rest for health problems and assistant coach Tran Cong Minh took the reins.
DTLA is now possibly the second V-League club to lose its coach this year. Ninh Binh moved head coach Robert Lim to the club's junior team, following a 2-2 home draw with Hai Phong Cement on Sunday.
The Singaporean coach left the position after just more than a month in charge of the northern club.
Ninh Binh is now second to last with only one point after four matches in the new season.