Newcastle United's record signing Joelinton faces disciplinary action after he appeared to breach Covid-19 regulations by getting a haircut.
"We are disappointed by the image shared by Joelinton," a club spokesperson was quoted as saying by British media.
"There are clear Covid-19 protocols in place and the club continues to guide and educate its players on their responsibilities.
What Fonseca would bring to Newcastle - Inside Europe
"The club will be taking appropriate action internally."
- Parker's Picks: Arsenal to beat United, Chelsea to win
- Opinion: Man Utd's terrible performance makes Arsenal favourites
Newcastle were the first Premier League side to be hit by a coronavirus outbreak earlier this season, leading to their training ground being shut down for 10 days.
Joelinton, who arrived at Newcastle for £40m from Hoffenheim in July 2019, has failed to justify his price tag, scoring just seven goals in 66 games in all competitions.
Newcastle, who have dropped to 16th in the table following a run of five successive league defeats, travel to Everton later on Saturday.
Are Liverpool the new favourites to sign Mbappe? - Euro Papers
Conte and Zidane on shortlist to replace Solskjaer at Man Utd - Paper Round
Newcastle, Man Utd, Man City and Arsenal battle for £50m Calvert-Lewin - Paper Round