The feeling was that if Stallone was, in fact, playing Starhawk than the role might not be the simply cameo that it was rumored to be, but based on this information it appears that Stallone only has the one scene.
The earliest rumors about who Sylvester Stallone would be playing in Guardians of the Galaxy Vol. 2 had him pegged as playing a member of the Ravagers.
If there’s more he’s not talking.
Recent information included the fact that his name was Stakar and while that led people to wonder if Stallone would be playing the comic book character known as Starhawk, due to the fact that Stakar was the character’s given name, it appears that part was pure conjecture, unless there’s more detail that’s not given in the production notes that were handed out at the critics screening, where our own Eric Eisenberg was in attendance.