The 23-year-old linked up with Guinea last week for a friendly against Cape Verde in Portugal, and registered an assist in a 2-1 win on Saturday.
“Hello everyone, unfortunately this morning I tested positive for COVID-19 whilst undergoing swabs with the national team,” the former Napoli man declared.
“I want everyone to know that fortunately I feel well but obviously I will have to respect the quarantine period. I hope to be at the coach’s disposal as soon as possible.”
Diawara becomes the fifth senior Roma player to test positive for the virus, after Antonio Mirante, Bruno Peres, Carles Perez and Justin Kluivert contracted the virus earlier in the summer.