Brooklyn Nets star James Harden has suffered an injury setback during his recovery from a hamstring strain and faces an indefinite layoff, the team announced on Tuesday.

A statement from the Nets said Harden’s injury had flared up during an on-court rehab session on Monday.

“Following an evaluation today which included an MRI, Harden will remain out indefinitely,” the team said. “Updates regarding his status will be provided as appropriate.”

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Harden has not played since April 5, when his return from a hamstring injury was cut short after only four minutes in a win over the New York Knicks.

The 31-year-old point guard is a key figure in the Nets’ hopes of mounting a strong challenge through the playoffs.

Brooklyn are second in the Eastern Conference with a 38-19 record, one game adrift of leaders Philadelphia.