Nene was assessed one technical foul and ejected at the conclusion of the third quarter of the Rockets' 126-99 win in Game 1 of the Western Conference semifinals.
Game 2 of the best-of-7 series is Wednesday night in San Antonio.
Nene grabbed Dedmon in the neck area in an attempt to push the Spurs center away from Rockets teammate James Harden after those two had gone face to face and exchanged words.
Officials quickly intervened before the situation escalated further.Dedmon and Harden each received a technical.
Nene tweeted after the game that there was "no bad blood" and that he was just trying to "protect my teammate."