I have based this trade concept on what I have read over the past few month's on Indy's interest to move Granger, Utah's interest in a new point guard, and recent news of our interest in Paul Millsap or possibly Al Jefferson.
Granger has one year left on his contract, so even if Utah does not like his injury history, they will like the size of his expiring contract as a trade chip during the trade deadline.
Indy needs better help off the bench, and I think that Bass and Lee or Terry would actually improve their depth both in their capacity to defend, stretch the floor, and score in limited minutes. They did not have great seasons this past season, but I blame that on the erratic nature of the Celtics season and chemistry issues more than the players. And even though they will be taking on about 11 mil in contracts for two players, that is still less than the 14 mil for Granger, and fills a bigger need for them than an injured Granger does--and I think he has been injured for the better part of three years now.
The Celtics, obviously need a center and a guy who can score. I think that Big Al fills that need more than Millsap, but the Celtics seem high on Millsap if reports are accurate. Either way they will take a similar amount of cap space probably 11-13 mil per year.
Maybe Indy wants a pick or Utah wants another pick, but basically I think this trade fits needs for each team involved, and the money works. So at the very least I can see a trade like this one happening on draft night or soon after.