Girona coach Michel Sanchez returned to work on Monday at the club's training ground after missing his team's defeat by Villarreal on Saturday under observation in hospital.
"As you know, I had a small health issue, doctors detected deep vein thrombosis in my left leg," the 49-year-old told a news conference.
"After tests, I was allowed to leave the hospital yesterday.
"I will undergo further examinations to determine the origin of the illness, but it has been diagnosed. I will return to a normal life."
Girona, who qualified for the Champions League after coming third in an outstanding campaign last season, are currently 15th and battling relegation.
Their 1-0 home defeat by Villarreal left them four points above the relegation zone with three matches remaining, including hosting Atletico Madrid on the final day.