Jonas Valanciunas

Toronto Raptors center Jonas Valanciunas has been ruled out of Game 1 of the Eastern Conference Finals.

(Gus Chan, The Plain Dealer)

INDEPENDENCE, Ohio -- The Toronto Raptors will not have starting center Jonas Valanciunas, the team's third-leading scorer in the postseason, for Game 1 of the Eastern Conference Finals against the Cleveland Cavaliers.

There doesn't appear to be much optimism for the remainder of the series either.

"He's going to get treatment day to day," Raptors head coach Dwane Casey said during a conference call on Monday. "I don't foresee it but I'm not committing to it. Just going to see how his body reacts and comes through rehab. It's going to be very difficult for Game 2. But to cancel him out for the entire series, I don't know."

Valanciunas, averaging 15.0 points on 55 percent shooting to go with 12.1 rebounds in the playoffs, has missed four straight games after suffering a sprained right ankle during Game 3 of the Eastern Conference Semifinals against the Miami Heat.

Since the injury, he hasn't done much on the court, only shooting free throws from time to time, as the Raptors continue to be cautious with their talented big man.

"We're not going to jeopardize further hurting his ankle just to get him out there for a game," Casey said. "If he's not 100 percent we're not going to damage it."

Fifth-year pro Bismack Biyombo has slid into the starting lineup, recording a double-double in three of the four games as starter.

"Obviously both of them has been a key to their success throughout the season," LeBron James said Monday following the final practice before Tuesday's series opener. "It gives them a different threat. They're able to throw lobs, he's able to finish over top. He plays with a lot more speed. Valanciunas is obviously very good, but they play a little bit more methodical game. Able to get out into the open floor with Biyombo. It gives them great balance when both of them are in there, and obviously with Biyombo in there since Valanciunas got hurt, has given them a different threat."

Biyombo, the seventh-overall pick in the 2011 draft, averaged 5.5 points to go with 8.0 rebounds and 1.6 blocks in his first season with the Raptors following four frustrating years in Charlotte.

"He found a home, having a chance to play some consistent minutes and Coach Casey has done a good job with him," Cavs head coach Tyronn Lue said. "Giving him confidence, telling him his role, he's knowing his role and he's playing to the best of his ability."

Getting a bigger platform to showcase his massive improvement, Biyombo's energy and relentless approach on the glass have helped the Raptors hold opponents to 94.1 points this postseason.

"He's a load," Kevin Love said. "He has really filled in well for Valanciunas. We don't know when we will see (Valanciunas) but (Biyombo) is a guy we have to keep off the glass, high energy, he'll tap some balls out to get some extra possessions, get to the free-throw line so he does a number of things to help them so he could be one of those guys we need to manage."

The Cavs have been preparing for the Raptors since Sunday night, after Toronto's 116-89 win against the Miami Heat, a game in which Biyombo scored 17 points to go with 16 rebounds.

At that time, the Cavs didn't know Valanciunas' status. Now they do. And it doesn't change Cleveland's plan.

"Prepare the same way," Lue said. "The only difference is they're not going to post him a lot like they do with Valanciunas. Everything else they continue to run. Not a big difference."

James, who knows all about navigating injuries this time of year, has stayed consistent with his message: The Cavs are focusing on how they can get better.

"Our approach doesn't change," James said. "Our approach is the same as if guys are in. If guys are out it's still the same. We want to wreak havoc defensively, we want to push the tempo offensively and it's been the same mantra of ours all season."