Miller left the game with 3:58 remaining in the fourth quarter after taking a hit while on defense. He did not return in the Heat's 92-84 victory in Game 1 against the Mavericks and left the arena wearing a protective sling to brace his left shoulder.
"It's just a little thing I'm dealing with, but I'll be all right," Miller told ESPN.com as he abruptly left the Heat's locker room and headed for the AmericanAirlines Arena garage. "I don't think it's a big deal. I'm OK. Believe me. I'm OK."
Miller said he did not have an X-ray or an MRI exam on the shoulder after the game. He initially bruised the shoulder last week in the final seconds of the Heat's Game 4 win against the Chicago Bulls as he attempted to fight through a screen. Miller entered Tuesday's game against the Mavericks wearing a protective sleeve that extended from his left shoulder to his wrist.
Heat coach Erik Spoelstra said after the game that Miller wore the sleeve "just to keep his arm warm," Spoelstra said. "He's fine."
Miller was 2 of 4 from 3-point range and finished with six points, five rebounds and four fouls in 20 minutes. He had been dealing with an assortment of injuries throughout the season, including severe sprains to both thumbs, knee soreness and concussion symptoms.
Miller also had been dealing with his infant daughter's illness that left her in an intensive care unit for several days after her birth two weeks ago. Miller's shoulder injury comes at a time when the Heat are short on long-range shooting depth.
Reserve forward James Jones, the league's three-point shooting champion, has been sidelined with a sprained left toe. Jones said after Tuesday's game that he would be ready to return to the rotation if needed.
The Heat are scheduled to practice Wednesday afternoon in preparation for Game 2 on Thursday.
Michael Wallace covers the Miami Heat for ESPN.com.