Friday 31 August 2018 11:35, UK
Moussa Dembele is unhappy that Celtic have blocked his proposed move to Lyon, Sky Sports News understands.
Brendan Rodgers confirmed on Thursday that Celtic had rejected a "significant offer", believed to be £18m, for the France U21 international.
Sky sources understand Celtic had previously assured Dembele they would not stop him leaving if an offer was received.
The 22-year-old was left out of Celtic's squad on Thursday night as the Hoops qualified for the Europa League with a 4-1 aggregate win over FK Suduva.
Dembele took to Twitter shortly before midnight to post an image containing the phrase: "A man without his word is nothing. A real man keeps his word."
Sky sources understand the message was aimed personally at Brendan Rodgers.
Celtic next face rivals Rangers at Parkhead on Sunday, live on Sky Sports Football.
