After a made CJ McCollum jumper with 5:15 left in the first half, Hayes was crashing the boards from the left corner when he plowed through Crowder, knocking him to the ground.
Initially no foul was called, but after Crowder sprinted up the floor to confront Hayes, and Suns guard Chris Paul immediately sprinted to another official, play was stopped and the play was reviewed.
It was determined there was windup and the contact was deemed unnecessary and excessive.
A minute prior, officials also reviewed a play with Hayes after he tried a two-handed block against Landry Shamet at the rim. That play was determined to be a common foul but tempers were still running high as Hayes and a few Suns exchanged words.
Hayes, who has been starting at power forward since the All-Star break, had four points and six rebounds. In the first two games of the series, he played a combined 31 minutes and had 13 points and four boards.
Crowder was assessed a technical foul on the play.