I think the Celts have approached Al's offense poorly in the last few games. They don't need him to be a big time scorer. They need him to pass, defend, and stretch the floor. They shouldn't ask him to post up one on one vs TT. That's a bad match up for the Celts. When TT is on the floor, Al should go out to the three point line to pull him out of the paint and open up driving lanes for Brown and Tatum.
The Celtic's offense is at its best when they search out mismatches. Get Al in the post against a smaller player, and when the double team comes, as it will, pass out to the shooters. Get Brown and Tatum on slower guys and attack the rim, if TT collapses to protect the paint, kick it out to Al for an open 3. They have been trying too hard to get Al going offensively, that plays right into the Cavs defensive strategy. Don't force feed Al in the post, attack the mismatches and I think the Cavs defense will fold.