Milan - Sampdoria forward Samuel Eto'o missed an afternoon training session which coach Sinisa Mihajlovic had ordered following their 5-1 Serie A defeat at Torino, Italian media said on Monday.
Mihajlovic had scheduled two training sessions on Monday, one in the morning and one in the afternoon, as a reprisal for his team's performance.
But Eto'o, who only joined Sampdoria last week from English club Everton, left after the morning session without speaking to the coach and did not return, media reported.
There was no immediate comment from either the club or the player.
Mihajlovic, a notoriously tough taskmaster who has revived Sampdoria's fortunes in his 15 months in charge, said he was ashamed by Sunday's performance, adding that his players needed to examine their consciences.
Former Cameroon forward Eto'o, 33, who was a free agent, joined the Sampdoria from Everton last week after only five months at the Merseyside club.
He came on as a second-half substitute in Sunday's match, only Sampdoria's third league defeat of the season.