Brian Windhorst tells Mike & Mike he's not expecting the Raptors-Cavaliers series to be a complete blowout and says that Cleveland might feel let down because they were priming themselves to play the Heat. (1:37)

Windhorst: 'Disrespectful' to say Cavs will walk over Raptors (1:37)

TORONTO -- Raptors center Jonas Valanciunas is out for Tuesday's Game 1 of the Eastern Conference finals against the Cleveland Cavaliers and is doubtful for Game 2 with an ankle injury, coach Dwane Casey said Monday.

Valanciunas missed the final four games of the Raptors' second-round series win over the Miami Heat with the injury. Casey didn't give a timetable on Valanciunas' return but said he wasn't yet able to participate in basketball activities.

Valanciunas suffered the injury in the third quarter of Toronto's Game 3 win over the Heat while contesting guard Dwyane Wade's layup attempt at the rim.

For the postseason, Valanciunas is averaging 15.0 points and 12.1 rebounds per game on 55 percent shooting. He was a team-high plus-39 in Games 1-3 against Miami.

Information from ESPN staff writer Mike Mazzeo contributed to this report.