Below are some on/off stats that I found interesting:
On Court: Fox, Barnes, & Sabonis / Off Court: NA = 113.6 OFF RTG / 117.5 DEF RTG / -3.9 NET RTG (278 minutes)
On Court: Fox, Barnes, Sabonis, & DiVincenzo / Off Court: NA = 111.0 OFF RTG / 105.2 DEF RTG / +5.8 NET RTG (83 minutes)
On Court: Fox, Barnes, Sabonis, & Mitchell / Off Court: NA = 109.6 OFF RTG / 130.8 DEF RTG / -21.2 NET RTG (51 minutes)
On Court: Fox, Barnes, Sabonis, & DiVincenzo / Off Court: Mitchell = 115.7 OFF RTG / 97.9 DEF RTG / +17.8 NET RTG (66 minutes)
On Court: Fox, Barnes, Sabonis, & Mitchell / Off Court: DiVincenzo= 118.1 OFF RTG / 127.8 DEF RTG / -9.7 NET RTG (34 minutes)
And just for fun (since it's very low minutes):
On Court: Fox, Barnes, Sabonis, DiVincenzo, & Lyles / Off Court: NA= 122.2 OFF RTG / 63.9 DEF RTG / +58.3 NET RTG (19 minutes)
The data is starting to suggest that we're a pretty effective team when DiVincenzo is paired with our 3 main guys (still lower minute totals though), and that jumps even higher when you remove the short, 3-guard lineup of Fox-DiVincenzo-Mitchell. The other lineups with Fox-Barnes-Sabonis-DiVincenzon in them includes Holiday, Lamb, & Lyles as the 5th guy. You see that the NET RTG is much higher when we actually put a full sized PF out there that can space the floor a bit (again, very small sample so take it with a grain of salt).
All the numbers I see suggest that a Fox-Mitchell backcourt has not been effective on the court together. It's why I'm not particular glued to keeping Mitchell if the idea is that we're building around Fox & Sabonis. We need our big minute guys to complement our core pieces - not clash with them. I know Mitchell talked about working on his game to fit better with Fox so perhaps we see how this data looks next year, but I think it's safe to say that DDV should absolutely be starting next to Fox next year with Mitchell coming off the bench.
Just to wrap it up, this suggests we have a pretty solid, well fitting 4 man lineup of Fox-DiVincenzo-Barnes-Sabonis that, more often than not, outplays the opposing team. If we can upgrade the PF spot with a complementary piece, who's to say this lineup couldn't be effective and win some ball games? We could try to address that via trade (PJ Washington, Jerami Grant, etc.) or the draft (Jabari Smith, Chet Holmgren, Keegan Murray, Tari Eason, etc.). My bet is that McNair is likely looking to address this in the draft and select Murray. It gives us the upgrade at PF we need, he can shoot the 3, he's a good defender, he can defend PFs, he can protect the rim, he can get out and run with Fox, he's a smart player that makes winning plays. Not to mention McNair was quoted as saying that he wants someone who can help now and help in the future. Murray seems to fit that mold as most feel he's more NBA ready while at the same time fitting our need at PF rather well.
PG - Fox / Mitchell
SG - DiVincenzo / Davis
SF - Barnes / Holiday / Harkless
PF - Murray / Lyles / Metu
C - Sabonis / Holmes / Len
Gives us a very well balanced, complentary starting lineup while also having a solid backup at every position (Mitchell-Davis-Holiday-Lyles-Holmes). Add a good coach this summer and perhaps we're looking like a playoff team come this time next year.