Diao has struggled with injury this season following his switch from Real Betis and has managed just seven games in all competitions.
He has now jetted off to Morocco to be with his team and Fabregas has made it known that he was not happy with the decision after speaking to Senegal head coach Pape Thiaw.
"I prefer not to go into the details of this matter," Fabregas said.
"Assane Diao knows my position very well, and I spoke to him after the Inter match.
"I also spoke personally with the Senegal coach, and honestly, it was not a pleasant conversation at all. That's why I completely distance myself from talking about this issue."
Como are currently in seventh place on the Serie A standings after 15 games and last lost 1-0 to Roma after a 4-0 thumping by first-placed Inter.