‘Our job is to hold it down’: Celtics big men Luke Kornet and Xavier Tillman continue to impress in preseason

With Kristaps Porzingis injured, and Al Horford not playing, they've made the most of their opportunity so far.

With Kristaps Porzingis out several months, and Al Horford unlikely to play every night, the Celtics will need to rely heavily on backup big men Luke Kornet and Xavier Tillman Sr. this season.

Through three preseason games, Kornet and Tillman appear ready to handle that increased responsibility.

“Our job is to hold it down,” Tillman told NBC Sports Boston’s Abby Chin after the Celtics’ 139-89 demolition of the 76ers on Saturday. “Each and every day, we’re working hard to prepare for moments like this. We’ll be ready, each and every game.”

Tillman, a midseason acquisition last year, averaged 4 points and 2.7 rebounds over 20 games with the Celtics. So far in the preseason (yes, it’s a small sample size, and yes, it’s worse competition), he’s upped those numbers to 9 points and 4.3 boards a night.

Perhaps the most encouraging development for the Celtics is Tillman’s improvement from 3-point range. After hitting just eight of 28 3s (28.6 percent) in those 20 games, he’s currently 6 of 8 (75 percent) in the preseason.

Tillman looks more comfortable shooting in rhythm, within the flow of the offense, as opposed to as a last resort. When asked how much work has gone into improving his 3-point shot, Tillman made it clear the growth didn’t happen overnight.

“A ton of work,” Tillman told Chin. “A ton, a ton, a ton of work. Me and coach (D.J. MacLeay), we put in a lot of hours with it. Then also just the mental piece. They’ve been doing a really good job with me, just telling me to launch it and not really think too much into it.”

Tillman credited Horford for serving as a mentor, both as a vocal leader and by example. He said his main focus over the next two preseason games is working on his conditioning and ensuring he’s ready to go when the regular season arrives.

Celtics coach Joe Mazzulla praised Tillman for his decisiveness and spacing.

“He’s worked really hard in the offseason just becoming more versatile,” Mazzulla told reporters.

Kornet, meanwhile, has seamlessly slid into the starting lineup and is averaging 8.7 points and 6.7 rebounds over three preseason games. He erupted for 15 points (on 7-of-10 shooting) and eight boards against the 76ers.

The 7-foot-2-inch Kornet naturally meshes well with starters Jrue Holiday, Derrick White, Jaylen Brown, and Jayson Tatum. He thrives in the pick and roll, passes well for his size, and has reliable hands and a soft touch.

The preseason debate at the moment is whether Horford or Kornet should start when both are playing. Who starts doesn’t matter all too much, but it’s clear Kornet is prepared for a surge in minutes.

“He’s worked really hard this summer, and I’ve definitely seen him get better,” Mazzulla told reporters.

Mazzulla called Kornet one of the Celtics’ best defenders because of his ability to communicate on the fly. He also said he’s gotten better offensively.

Brown highlighted Kornet’s ability to be in the right place at the right time and said the Celtics are looking to him to step up.

“I’ve been able to play with a lot of those guys for quite a few years now,” Kornet told reporters. “We had a lot of advantages on the court today, so it was a little easier than we’ll probably expect it to be. But yeah, I think it’s a pretty solid starting point.”