MAVS NEWS:

[StrandedOnBeauboisHill]

Two parts to my answer ...

1  I have not been addressing the financial possibilities at all. None of what I have said has had any real connection to the extension question. But if I go there now: I don't think extending him is going to be a viable option, because I don't think either side will like the other's numbers. Here's how I think it is most likely to play out.
....MAVS - Because of his injury history, DL will have to "prove" to them he can stay healthy before the they make a bigger commitment. But imo it's way too late in the timeline for that, because the window for an extension opens and closes next summer. The BEST he can offer by that point would be that he's been healthy for how long - a half season in a row? - and we can't even assume that much will be true. Mavs offer will come in fairly low, but of course they will want him to extend at that number. 
....DL - He won't want to be locked into a lower number and will ask for a big number. And frankly, is Dallas the team he can trust his medical maintenance and recovery to their staff? So he will decline the extension they offer, play out season 4, and try to prove himself in season 4 after which he will be RFA. It will play out like Josh Green did, and with similar angst in the discussions featuring major alarmism over how the Mavs blew it and now he will cost $200M or so.
....Once he's a RFA in summer 2027, both sides will see how much the rest of the NBA values him, and both sides will figure out how they want to navigate things from there. IMO no way to avoid that, and it brings no guarantees. The Mavs will only have to pay what someone else will offer. Who knows what others will be willing to pay? But all of that makes his long-term future in Dallas a bit uncertain, and based on his inability to stay healthy, rightly so.

2 However --- My "position" has nothing to do with extensions or next contracts (because they aren't at that crossroads yet, and likely won't even be there until the summer of 2027). And there's no good way to talk trade either -- the Mavs don't know his long-term value, other teams don't know it either, and neither do we, so everything with him is in a long-term holding pattern to see what emerges.

What my position is -- ie the point I have been making -- is that, with his injury history being so ongoing, and no end in sight, anyone who is planning on him as a MAVS' BUILDING BLOCK for the future and as a FUTURE STAR CENTER is ignoring all the facts up to this point. So far he is always just another injury waiting to happen. He is also a looming financial nightmare to deal with in 2027 from which we can't be sure he remains a Mav. And his past production has been so limited minutes-wise that we certainly can't say his future presence will give us many years of top-tier center play -- out of the 4000 minutes per year at center, will he even be able to ever play as many as 1500 in a season? If we guesstimate that in future years he will be playing 40-55 games each season (due to injuries and injury "management"), and will average 20-25 mpg, the UPPER extreme of that has the Mavs only getting 1375 minutes from him per season. That's not enough minutes to be a solution at C, or to pay big money for, or to get major impact from.

SUMMARY of my position is this - We can't and shouldn't make plans that say "We have the center position filled with a great center solution for the long term, because we have Lively -- and he's only 21."

Is it possible that it all changes in the future and he's healthy and plays full time? Sure, it's possible. But that's not what we should expect at all, because he has NEVER been able to do that, ever.

Sorry on the delay here, this all makes total sense and probably the likely way this all plays out at this point (unless he returns and just lights it up the second half of the season but that doesn't really feel like it's in the Mavs best interest anyway for a handful of reasons so they could prevent that even if it is a possibility).

I guess the only place I differ on is this idea of planning for him to be a building block, I don't think most on here are assuming that's like a done deal anymore so I'm certainly not going to argue against that.  I think though when it comes to asset management, there's now this fine line with Lively where you don't want to fall into sunk cost fallacy but you also don't want to give up too early on him and spend assets on a center when there's still a sliver of hope.  Luckily I think this lottery they won't be faced with that issue given that this isn't a super big heavy draft and taking BPA should end up being a no brainer but I do think there would be conversation if there was a big man they REALLY liked.  It just sucks because acquiring him used such a valuable asset so while I'm teetering on falling into that sunk cost fallacy, I still think you continue to build thinking that him getting healthy and becoming that building block is pretty equal odds to whatever other young center you could acquire by whatever means becoming a building block so I'd still think it's prudent to build around the edges.  Does that have a decent probability with all this coming back and having to address the center position anyway long term?  Sure, but again, this team is in a rough place and the light is far away down the tunnel for that gamble not to hurt too badly.