Manchester United defender Phil Joneshas been suffering from "mild thrombosis" and the England international footballer will miss at least three weeks of the English Premier League (EPL) season.
Jones, 23, was left out of United's squad for the opening game of the EPL season on Saturday due to the blood-clotting problem, dailymail.co.uk reported.
Thrombosis is a clotting of the blood in a part of the circulatory system.
The issue means the former Blackburn centre-back will miss Premier League games against Aston Villa, Newcastle United and Swansea City as well as home-and-away meetings with Club Brugge in the Champions League.
His participation for England in the upcoming internationals against San Marino and Switzerland could also be called into question.
Jones trained with his teammates at their Carrington training base earlier this week but was unavailable for competitive action on Saturday.