James sustained the injury late in the third quarter of Monday's 117-94 victory against the Utah Jazz when he tripped over his own foot while attempting to drive to the basket in transition. James left the court and sat out the first seven minutes of the fourth quarter before returning and finishing the game.
The four-time league MVP is expected to receive treatment throughout Tuesday and into Wednesday before his status is determined for the matchup between the teams with the best records in the Eastern Conference. The Pacers beat the Heat 90-84 last week in Indianapolis.
Speaking after Tuesday's practice, James said his ankle felt "about the same" as it did Monday night and that he would not have played if the Heat had a game Tuesday.
"Very stiff, very sore," James said. "Like I said, I've had my fair share of ankle twists. I already knew what it was going to be [like] today. I'm going to be [in] around-the-clock treatment. We've been through this, so we know how to attack it."
James has been working with longtime personal trainer Mike Mancias, who followed him from Cleveland to Miami, through an array of nagging injuries this season. James had been dealing with a sore back since the middle of training camp, and he's also aggravated an ankle sprain twice this season in addition to playing with two jammed fingers.
"It's been to the point where I've been able to play the next game, to the point where I've had to miss a few games," James said of dealing with ankle sprains throughout his career. "I've had the extreme to the not-so-extreme. Basically, it's a mental thing at that point."
James is the only Heat player to start every game this season and is one of two players on the roster to play in all 24 of Miami's games. James has missed a total of 10 games during his 11-year career with ankle sprains.
Center Chris Bosh suggested that James would definitely play Wednesday because he's seen his teammate overcome just about any injury.
However, coach Erik Spoelstra was more cautious with James' status.
"Treatment was better," Spoelstra said. "It's not the first time he's gone through it with that ankle. A lot of treatment today, a lot of rest, and we'll see how he feels tomorrow."
James is coming off his best set of performances of the season, having flirted with triple-doubles in the past two games. He had 25 points, nine assists and nine rebounds Saturday against the Cavaliers and 30 points, nine rebounds and nine assists in 34 minutes Monday against the Jazz.