In 2013–14, Haslem lost the rotation spot he had long occupied. His on-court time continued to significantly diminish as the season progressed. Haslem played in just seven games in January and February combined, and played only two total minutes from January 21 to February 27. Haslem played in just 46 regular-season games in 2013–14, averaging 3.8 points and 3.8 rebounds. The Heat returned to the NBA Finals in 2014 for the fourth straight year, where they were defeated in five games by the Spurs. Following the 2013–14 season, Haslem decided to opt out of the final year of his contract.
Haslem re-signed with the Heat on a two-year deal in July 2014. He re-signed with the Heat on one-year deals in 2016, 2017, 2018, and 2019. In January 2019, Haslem indicated that the 2018–19 season would be his last. In April 2019, however, Haslem stated that he had not decided if he was retiring and the decision would not be made until the 2019–20 season. On August 6, 2019, Haslem re-signed with the Heat to a one-year contract. Over a year later, on August 14, 2020, Haslem played as a starting power forward in a loss to the Indiana Pacers during their season finale. During the 2019–20 season, he became the 30th player in league history to play after turning 40 years old, as well as the first modern era undrafted player to play to that age. The Heat reached the 2020 NBA Finals, but lost in six games to the Los Angeles Lakers.