It would be easy for the Celtics to rely on being shorthanded as an excuse because they were missing two starters in Friday’s showdown with the top-seeded Cavaliers.
But they should play the long game mentally after a 123-116 loss in which they blew a 17-point third-quarter lead. They could see the Cavaliers in the Eastern Conference finals and they won’t have home-court advantage.
Cleveland took the final regular-season matchup against the Celtics seriously. The Cavaliers were healthy, and after falling behind, 25-3, they methodically chased down the Celtics with their depth.
And depth, or lack thereof, should be the primary concern for Boston because it is good enough to clinch the No. 2 seed but a playoff rematch with Cleveland could pose a serious issue.
Celtics coach Joe Mazzulla kept his rotation tight despite the absences of Kristaps Porzingis and Jrue Holiday to injury. Despite playing a third game in four nights, Mazzulla used mainly seven players with Drew Peterson (one minute) and Torrey Craig (three minutes) making cameo appearances.
The Celtics reserves were outscored, 33-6, which overshadowed a brilliant combined performance from Jayson Tatum and Jaylen Brown (83 points on 32-of-61 shooting). Of course, the Celtics would have been deeper and more effective with Porzingis and Holiday but Mazzulla’s tight rotation allowed his team to become predictable.
The Cavaliers targeted Sam Hauser and the 6-foot-8-inch swingman with the balky back was left to defend the shifty Darius Garland, who has as many moves as Barry Sanders. And if it wasn’t Garland, it was Donovan Mitchell calling for screens from Hauser’s assignment to create the matchup.
“He’s been a great defender in the league for the last two, three years and earned a reputation in that,” Mazzulla said of Hauser. “The confidence comes from having him in the game, being able to defend.”
Craig was signed to be a wing defender and 3-point shooter, and yet he sat the whole second half after getting a DNP Wednesday at Detroit. He could have made a defensive impact. With Mazzulla deciding months ago that Xavier Tillman was unplayable and being iffy on Neemias Queta, Luke Kornet was the lone backup big man who saw minutes.
Kornet was a minus-26 in his 19 minutes and that was a problem. He couldn’t keep All-Star Evan Mobley off the boards and provided little rim protection. With Tillman and Queta basically relegated to emergency duty, it shortens the bench and limits Mazzulla’s options.
Boston still has a roster spot available and picking up a buyout player or free agent would be pricey because of the luxury tax implications, but another body wouldn’t hurt in the final 22 games. The schedule is rigorous, with Denver, the Los Angeles Lakers, and Oklahoma City coming to the Garden in the next 12 days.
Mazzulla is going to need to see whether Craig can be a playoff rotation option. The Cavaliers used 10 players Friday and all five reserves were pluses, including a plus-34 from Sixth Man of the Year candidate Ty Jerome and plus-21 from newly acquired De’Andre Hunter, who was acquired for these situations against the Celtics.
Hunter did little to contain Tatum or Brown, but he scored 12 points and nailed three 3-pointers. It’s the first time the Celtics have seen Hunter in a Cleveland uniform and his presence could loom significant in a playoff series.
Of course, the Celtics will be better when they’re whole. And the Cavaliers also received 26 points in 19 second-half minutes from Mitchell. The presence of Holiday should help that issue but it wouldn’t hurt if Mazzulla offered an opportunity for Craig and Queta to carve out playoff roles.
It’s not the first time a team has targeted Hauser defensively and he struggles with quickness and lateral movement. It’s not for a lack of effort, but Hauser’s not on this roster to stop anybody. He’s here to spread the floor and capitalize on defenses sending two at Tatum or Brown and splashing corner threes.
In the second half, the Cavaliers chased the Celtics off the 3-point line — limiting Boston to a meager 13 attempts — which dismantled their offense. After both teams combined for 138 points in the first half, Cleveland won the slower-paced second because it defended and rebounded better.
But it is also difficult to win when the Celtics besides Tatum and Brown combine for two baskets in the second half. That makes Boston much easier to defend.
“I thought both of those guys’ shot selections were tremendous at times,” Mazzulla said. “I don’t think it’s about predictability. It’s just about making the right play, whatever that may be. I thought for the most part we got the shots that we were looking to get.”
The Cavaliers will be essentially the same team if these clubs meet in the Eastern Conference finals. The Celtics will have two more important contributors, but it wouldn’t hurt for Boston to take the information gathered from this game and perhaps spend the next 22 learning whether they can get more out of their bench in the postseason.
“It was definitely an intense game and you could tell they wanted to beat us and we came out swinging,” Brown said. “And we had enough. We had enough to win the game despite who was sitting out. Whatever. We should have won this game. A couple of impressions we can improve on. We could make smarter decisions. A few plays I wish I could have back. We were aggressive for the most part and they hit shots. Got to give them credit.”
Gary Washburn is a Globe columnist. He can be reached at gary.washburn@globe.com. Follow him @GwashburnGlobe.