Luxury tax comes from contracts owned by the Cavs at the end of the regular season or waived during the season.
Luxury tax is only counted for the amount paid by an NBA team during the season, not any amount paid by the league. Since he was on a 2nd year min salary contract, the NBA does not pay any portion of his salary. (NBA pays a portion of the contract on min salary contracts > 2nd year min salary contracts and that NBA portion does not count twards the luxury tax)
If he leaves the team now, he stops geting paid. He would have been played 54 out of 82 games + 5 preseason games, or 68% of the season.
So I estimate that he'll cost about 1.13Mil against the luxury tax at the end of the regular season unless the Cavs trade his contract.