Chicago Bulls point guard Rajon Rondo is out indefinitely after suffering a fractured right thumb that will not require surgery, the team announced on Friday. It is unclear when he suffered his injury.

Rondo’s injury has been described as “pretty serious,” according to ESPN’s Chris Haynes, and his return may be dependent upon how long Chicago can extend its postseason.

Rondo played 40 minuted in the Bulls’ Game 2 win over the Boston Celtics, posting a near triple-double with 11 points (on 5-of-11 shooting), 14 assists, nine rebounds, and five steals. Chicago outscored Boston by a team-high 24 points with its starting floor general on the floor.

The injury is a debilitating blow to the Bulls, who have taken a 2-0 series lead over the Celtics with the series headed to Boston but do not have a reliable backup point guard. Jerian Grant has played well in very limited time, but is only in his second season. Michael Carter-Williams has virtually fallen out of the rotation.

Rondo also helped guide the Bulls to victory in Game 1, posting 12 points, eight rebounds, six assists, and two steals in 27 minutes. Bulls head coach Fred Hoiberg called his veteran point guard “a rock for [the team] all season long.”