Haslem went down late in the third quarter while defending Grizzlies forward Zach Randolph in the post. Haslem collapsed without jumping and immediately grabbed the middle of his right foot and called for attention from the bench.
Moments later he was carried off the floor, unable to put weight on the leg. As he was being attended to, teammates crowded around him.
X-rays were negative and Heat coach Erik Spoelstra said Haslem will be re-evaluated Sunday in Miami.
Losing Haslem for any length of time would be a blow to the Heat, who have struggled at times this season defending opposing forwards and centers. Haslem is the team's leading rebounder and entered the game leading all NBA reserves in rebounding at 8.8 per game.
"What I've heard is, I mean I haven't heard from any docs, but he dislocated his second toe and he tore a few ligaments in his foot somewhere," LeBron James said. "I don't know how long he'll be out but anytime one of your teammates go out it hurts."
"He's like our heart of our team. He's our power. He's our pride. He brings everything every night," James said. "Size never really matters to him. He always plays above his height, plays above his weight."
Heat forward Chris Bosh said it was not a good sign that the ever-tough Haslem was carried off the court.
"Unfortunately the game goes on," Bosh said. "You're always going to have to play through adverse situations. I think we did a decent job of responding. We just came up a little short."
Brian Windhorst is an ESPN.com NBA writer. Information from The Associated Press was used in this report.