Keita Balde Diao says he has been "profoundly hurt" after Lazio left him out of their squad for the Italian Super Cup.
The striker has been heavily linked to Juventus -- Lazio's opponents on Sunday -- all summer, with a bid for Keita rejected last month.
Lazio said the Senegal international was out with a muscle injury, but he denied that in a statement on Twitter.
"The lack of a call-up for the Super Cup Final has profoundly hurt me," Keita wrote in Italian. "It is the first important match of the season, for which I had prepared and was ready for action.
"The decision made by the club, which evidently had nothing to do with purely sporting criteria, puts me in a psychologically uncomfortable position and right now I don't know how to evaluate the consequences of that."
Lazio coach Simone Inzaghi said earlier on Saturday that he was concerned about getting a full effort from Keita.
"There are rumours around Keita and I will observe everything," Inzaghi said. "In my mind, players need to give 100 percent. If I can see that in Keita, then he'll play, otherwise I'll look to someone else."
Keita is entering the final year of his contract, meaning Lazio are running out of time if they want to cash in on the 22-year-old before he's able to sign a pre-contract in January and leave for free.
Meanwhile, Felipe Anderson was named to Lazio's squad despite injury concerns.