In general, it is rare for any team to change its starting lineup in Game 1 of a playoff series. It's rarer for that change to come ahead of Game 1 of the NBA Finals, and practically unheard of for a heavy favorite to do so under those circumstances. The Oklahoma City Thunder won 68 games in the regular season. They'd outscored their playoff opponents by 221 points in nine home games entering the Finals. Why on Earth would they be the ones to adjust before a series even began?
Well, they did so for Game 1, starting Cason Wallace over Isaiah Hartenstein in a 111-110 loss. It was their first starting lineup change of the postseason, and it was a controversial one. They hadn't even played a game yet and they were already letting a team that won 18 fewer games than they did dictate their lineup choices? Why not use Game 1 to feel out the matchup? Why give Indiana the intangible advantage of knowing it scared the Thunder into making such a change? The simplest explanation lies in Indiana's path to the Finals.
The Pacers faced three teams in the Eastern Conference playoffs that were capable of playing double-big lineups. They decimated the Milwaukee Bucks by 32 points in the 64 minutes that Giannis Antetokounmpo and Brook Lopez played together. In the 124 minutes Antetokounmpo played without Lopez, the Bucks were outscored by just three points. The Cleveland Cavaliers were outscored by 7.9 points per 100 possessions in their Indiana series when Evan Mobley and Jarrett Allen played together despite posting a monstrous rebounding rate of 57.3%. Even the Knicks, who made a much-discussed lineup change to attack Indiana with a double-big lineup, ultimately fared better when Karl-Anthony Towns played without Mitchell Robinson (+7 in 136 minutes) than with him (+0 in 75 minutes).
The Thunder reasoned, maybe correctly, maybe prematurely, that no double-big lineup could keep up with Indiana's speed. Mark Daigneault didn't just remove Hartenstein from the starting lineup. He didn't use Hartenstein and Chet Holmgren together for a single second. In fact, he even devoted quite a bit of time to lineups featuring neither of them. Hartenstein played only 17 minutes. Holmgren played 24. That meant that there were around seven minutes in which he used neither, going ultra-small against Indiana mostly using a lineup of Wallace, Shai Gilgeous-Alexander, Lu Dort, Alex Caruso and Jalen Williams.
That lineup was the group that lost Oklahoma City the game. Wallace came in for Holmgren with 3:24 remaining on the clock. Gilgeous-Alexander made a free throw, and then the Thunder were outscored 13-4 to blow Game 1. It wasn't the one-big lineup that doomed Oklahoma City. It was the tiny, no-big lineup that did so in the end.
It was by no means decisive, but the new starting lineup ultimately won its minutes by two points. Holmgren lineups won theirs combined by four, and Hartenstein lineups won theirs by two. The one-big Thunder, broadly, were better than the Pacers in Game 1, and even if the Thunder were winning with two-big lineups for most of the postseason, they weren't necessarily winning because of their two-big lineups. In 201 playoff minutes, the Thunder have only outscored their opponents by six points with both Holmgren and Hartenstein on the floor at the same time.
Drill down to the specifics and things get even murkier. The Thunder have scored only 107.7 points per 100 possessions with both big men on the floor this postseason. The floor starts to get a bit cramped with both of them, but unlike, say, the Knicks or Rockets, Oklahoma City hasn't dominated the offensive glass enough to compensate with their own two-big unit. Their offensive rebounding rate of 28.3% would be below-average by regular-season standards, and the Thunder likely fear that having two big men on the floor would make them vulnerable defensively.
Take a look at the tracking data. Tyrese Haliburton has attempted at least 15 shots against six different defensive players this postseason, and four of them are bigs: Towns (24), Allen (20), Bobby Portis (20) and Robinson (16). He loves to hunt centers. By bringing Hartenstein off of the bench, he gets to avoid as many Haliburton minutes as possible. He's not as vulnerable as, say, Towns is, but defending on the perimeter isn't his strength. It's what the Pacers starters would force him to do because Myles Turner is such a good shooter. The Knicks tried playing drop-coverage against him. It went badly.
And that's before considering what taking Holmgren off of Turner does. He can't chase Indiana's perimeter players, all of who are too dangerous to be ignored as shooters. That means he would have to defend Pascal Siakam. Could he do so? There's not an easy answer there. His length would be a real weapon against Siakam's fadeaway jumpers. He'd also be giving up some strength and risking foul trouble.
Defense and rebounding are the reasons to use two big men at the same time. If the Thunder have doubts on both fronts, sticking with one at a time makes a lot of sense. The question here probably isn't "should the Thunder go back to starting Hartenstein and Holmgren together," but rather, "what lineup adjustments do we need to make within the one-big framework to regain control of this series?"
If Game 1 was any indication, the zero-big lineups should probably be axed. They play into Indiana's hands, and the Pacers have a meaningful rebounding advantage with Siakam as their small-ball center. The rotation also probably needs to be tightened up. Why on Earth did Ajay Mitchell play non-garbage time Finals minutes? He's a rookie who has mostly been confined to garbage time so far this postseason. Daigneault likes to play deep rotations. Now is not the time to get cute. It's the NBA Finals. Isaiah Joe's defense needs to be watched carefully as well. He made his shots in Game 1, but he's the sort of mismatch the Pacers like to pick on.
That's the easy part. The harder one is the starting lineup. We've established why the one-big look makes more sense, but it's worth wondering if Wallace is the ideal replacement for Hartenstein. The Thunder lose around seven inches in wingspan and nine inches in height through that swap, and the Pacers exploited that. While Wallace is a terrific defender of guards, he's vulnerable against bigger forwards like Siakam. The Pacers looked for that matchup quite a bit in the early going, and considering how much switching the Thunder do, it's one they're going to concede some with Wallace on the floor.
The obvious counter here? Start Caruso over Wallace. If he's not vulnerable against Nikola Jokić, he's not vulnerable against a single soul in this entire sport. He can hold up in the post on Siakam, but he's also far better at ball-denial in the post, as we saw against Jokić.
The Thunder surely considered this. Wallace probably got the nod for offense. He's the more reliable shooter of the two, and Caruso has never been an especially high-minutes player. He played 28 to Wallace's 33 in Game 1, and he averaged just 19 in the regular season as the Thunder tried to manage his workload to keep him fresh for the playoffs. The more you use him, the less intensity he's able to bring to every possession. That's a tradeoff Daigneault will have to balance.
There's no perfect solution to the Pacers. That's what got Indiana here in the first place, and it's what motivated Daigneault's surprising lineup change. Caruso is probably the best of the imperfect answers, but as Game 1 showed, this series isn't going to be the walkover many expected. Oklahoma City can't rest on its 68-win resume and assume it can sleepwalk to the title. Daigneault knew that. Now, everyone else should too.