Leicester and England forward Rowntree was cited by an independent match commissioner for allegedly punching an opponent during the Lions' 17-13 victory over Auckland on Tuesday.
But Rowntree was cleared, and is now free to continue playing, putting him in the frame for third Test selection against New Zealand on Saturday.
Lions boss Sir Clive Woodward will announce his Test team on Thursday, with Rowntree strongly tipped to clinch a starting place.
Meanwhile, Auckland centre Sam Tuitupou received a six-week ban after being cited for stamping during the game.
The 23-year-old also appeared at a disciplinary hearing in Auckland, where he pleaded guilty to stamping on Lions centre Gordon D'Arcy.
Tuitupou is now sidelined from rugby until August 19.