Malcom, 21, was seemingly poised for a move to the Italian capital from Ligue 1 side Bordeaux, with both club's announcing an agreement on their official social accounts.
However, in one of the most sensational transfer hi-jacking's in recent memory, the Brazilian opted for a last-minute move to Barca in a €41m (R631m) deal.
"I don't know who he is, I don't know him," the Greek defender told reporters in Dallas in the ICC pre-match press conference. "Before he signed for Barcelona, even he didn't know his name.
"There is no reason to say hello. He didn't want to go to Roma, it is better that he goes to Barcelona."