2024 NBA Finals X-factor: Boston’s Xavier Tillman Sr. proving valuable in place of Kristaps Porziņģis

DALLAS — With Celtics center Kristaps Porziņģis sidelined from these NBA Finals due to a rare leg injury, a torn medial retinaculum that ruled out the 7-foot-2 marksman from Game 3 and perhaps the rest of this series, Boston head coach Joe Mazzulla contemplated how to tweak his lineup for Wednesday night’s 106-99 win against Dallas. There, in his bullpen of bigs, waited Luke Kornet, himself a 7-footer who began his NBA career clipping 3-pointers for the New York Knicks. Mazzulla instead called upon 6-foot-8 Xavier Tillman Sr. as the Celtics’ first reserve to touch the American Airlines Center floor.

Tillman joined Boston this past February, one day before the league’s annual trade deadline, by way of a deal with Memphis. Mazzulla recognized Tillman’s familiarity with Dallas from three years residing in the Western Conference while guarding Luka Dončić within the Grizzlies’ similar heavy-switching scheme. Sure enough, there was Tillman, staying in front of Dončić early in the second quarter, and then blocking his shot off the glass before securing the rebound. Two minutes later, he withstood Kyrie Irving charging at him at full speed, forcing the shifty ball-handler to change directions and botch a left-handed push shot. “He was moving his puppies,” Mavericks center Dereck Lively II said. “Got to tip your hat to that.” Late in the third quarter, Tillman then walled the paint from Dončić again, leaving the Mavericks’ All-NBA falling away from the basket and his layup short.

“He held his own, time and time again,” said Al Horford, Boston’s starting center. “He was just ready for the moment.”

The fact Tillman turned in 4 rebounds, 2 blocks and a critical third quarter 3-pointer, while netting a plus-9 in 11 minutes, is not the achievement. He has showcased a well-rounded ability over four total seasons in the NBA since becoming a second-round draft pick in 2020, to the point over a dozen teams, according to league sources, seriously pursued Tillman’s services on the trade-deadline market. Aside from Boston, Tillman remembers hearing Phoenix as another strong possibility. It’s the fact Tillman could produce such a performance, on such a stage, after not playing in each of these Finals’ first two games, and not miss a beat.

“Big shout out to X,” Derrick White said. “To not be in the rotation but to stay locked in and he gives us big-time minutes, plus-9, and he just does a little bit of everything out there.”

Tillman didn’t have to get ready because he stays ready. He describes himself as robotic with his routine, approaching each contest with the same regimen as if he’s going to play no matter what. Since his trade to the Celtics, Tillman’s pregame process has adapted to include solving sudoku puzzles from his locker-room chair. After watching her husband previously prod through those nine numbers on a phone app, Tillman’s wife, Tamia, gifted him a pocket-sized spiral notebook of the logic-based grids when their family was moving to Boston. He’s taken it with him almost everywhere since, stealing an hour whenever he can to attempt his next page.

“It’s good for the brain,” Tillman told Yahoo Sports. “Just to kinda get you thinking and it gives you confidence when you’re solving stuff like that.

Tillman was solving puzzle No. 79 out of 211 in the booklet at his locker prior to Game 3, leaving black ink across the white paper from a pink pen. “I’m not putting nothing down unless I know for sure that it goes there,” Tillman said. The gift was originally intended as shared competition between the couple. Tamia has her own copy. At first, they were filling out each page under the lamplight before bed. “We maybe did like three,” Tillman said. “And after that, I just kinda took off on my own.”

His mother recently took a try, but attempted no strategy. “She has a page in here that she just completely ruined,” Tillman said. But the further Tillman flips through the book, the more challenging these puzzles progress, the more he finds each stroke of his pen a soothing way to take his focus off the game he can’t stop thinking about. He has learned certain patterns that he prefers to crack each code. Somehow, he manages to be successful while listening to podcasts through his AirPod Max headphones. Tillman’s downloading episodes of "Serendipity" with Inky Johnson, the motivational speaker whose college football career ended at Tennessee due to a paralyzed right arm. The morning of Game 3, Tillman listened to a sermon from Transformation Church. As he prints the numbers onto these pages, he’s also prone to cueing up financial programs as well. The one thing Tillman won’t do is take pen to puzzles during Boston’s team charters. “Nah, not on the plane,” he said. “I play Booray on the plane.”

Once the pregame clock strikes 55 minutes until tipoff, Tillman puts down his paper and begins that regimented warmup. “You gotta just make sure that you’re doing everything in your power to be ready rather than get your name called and not be,” Tillman said. He does the same foam rolling to activate his tendons and muscles. He does the same stretches, the same body movements. “Just different band work and stuff like that,” Tillman said.

He wasn’t fully ready for the breadth of Boston’s season. He had tunnel vision, on the direct assignments Mazzulla believed, but proved advantageous against Dallas on Wednesday. After his arrival from the Grizzlies, Tillman was still nursing a knee injury, and his first few games were spent watching the Celtics from their bench. “We were just winning every game. I was like, ‘Damn! We’re good,’” Tillman told Yahoo Sports. “Then I checked the record, I was like, ‘Oh, we’re really good.’ It took me a second, probably a couple weeks to realize how good we were and the potential opportunities we could have.”

Now, he’s capitalizing on his own, helping Boston’s dreams become reality. With just over two minutes left in the third, amid Boston’s burst that would build a 21-point edge that proved to be insurmountable, Tillman collected a pass from Jaylen Brown in the right corner and splashed home a triple. Brown told reporters he drove against Dallas’ defense knowing it would collapse and it would leave Tillman all alone. “And I trusted it all the way. I just knew it was going in. I don't know how to tell you,” Brown said. “It was just like a divine experience. I knew X was going to make that shot.”

“These are the types of games people remember forever,” Horford said. “The type of impact [Tillman] had."