Marvin may be re-signed, the Jazz have the #5 pick in the draft, Tomic may come over, and the Jazz have additional cap space. There are a number of plausible scenarios that have one or or both Burks and Kanter coming off the bench and/or playing less.
Marvin could be re-signed, but it would be a scaled down contract. Also, his role would be reduced. Burks and Kanter would be RFAs at season's end, and so they would need, and want to see as much of them as possible. Marvin has value, but the data last year clearly tells Burks and Kanter outperformed him. His veteran presence could be even more valuable off the bench playing alongside all of our potential rookies: #5, #23, #35, Neto, and Tomic.
Tomic won't be prepared to start and play 82 games. If they see him as a starter, I am sure he will be worked into that role, having to earn it, and not thrown into it. Remember, Tomic has only ever played 20 something minutes like once a week. How is he going to go from that to starters minutes without a hitch?
Who at #5 is ready to start from day 1? Who are they beating out? #5 has a lot of players w/ a lot of upside. Not players who'd be ready or deserving of starting on day 1. Starting Trey all last year was done because the other options were JLIII, Tinsley, and eventually Garrett. Kanter and Burks are farther along than everyone available at #5. Some at #5 may have more upside, but I am sure Jazz won't just hand over the keys like they did with Trey. Different situation.
Cap space - yes, we have it, but who are we grabbing that deserves to start of Kanter and Burks? If we're not contending soon, we should be developing, otherwise, we are "skipping steps." Also, the FO could ink Hayward, Kanter and Burks this offseason, which would have Hayward, and favors on non rookie deals, and kanter and burks the following year. It's a tricky time to be bringing on free agents of significant value, unless their deals are very short.
I think the most likely scenario is we see
Trey
Alec
Gordon
Enes
Favors
As a starting unit, at least until the trade deadline.