I have always been curious about Bagley. Numbers always seemed good. Has the NBA body. But for some reason, SAC didn't seem to want him as part of the future. There is probably something to that, just not clear to me what that something may be.
As to Bagley's offseason, he is a RFA with a qualifying offer of about $14.8M. I think Detroit can make that QO to him if they want. He would end up in a situation much like Markkanen last offseason where his best offer may not even be more than the QO. To get him, we would likely have to do a sign and trade which would hard cap us. I don't expect the Celtics to do a S&T for that reason but it is possible.
To me, in theory at least, he is exactly what we need. An athletic, full-sized big with some ability to score. He is not a 3pt shooter but he is a career 14'ish points, 7-8 rebound player, even under the less than ideal conditions he has played in.
Probably the best thing for him to do is to take the QO from Detroit (assuming they offer it) and try to show the league something. Then hit it as an UFA and try to cash in big.