CANTON, Mass. — Tommy Heinsohn had been lounging on the leather sofas in the pop-up green room, coffee and donut in hand, when a photographer called for him. In an instant, the 85-year-old Heinsohn was boxing out television tag-team partner Mike Gorman in front of two gigantic blue-tinted mirrors while a crew filmed new promotional materials for NBC Sports Boston’s coverage of the Celtics 2019-20 season.

“This is a production and a half,” Heinsohn said after his morning duties were complete. "TV came to the NBA way long ago but now they've learned to truly exploit the medium. So here we are standing in front of mirrors, jumping up and down and smiling and dribbling basketballs.”

No one needs to prompt Heinsohn to smile when he proudly announces that this is his 64th consecutive Media Day with the Celtics, a streak that began with his rookie season in 1956. No official records exist but those around the NBA are fairly certain Heinsohn holds the record for most consecutive media days with one team — and by a comfortable margin.

Just how absurd is Heinsohn’s 64 total media days? The 18 Celtics who participated in Monday’s event at High Output studios have a combined total of just 59 media days between them.

Before the Celtics huddle for the first training camp practice on Tuesday, Heinsohn sat down for a Q&A about the growing Media Day spectacle and the upcoming season:

Q: What was Media Day like in 1956?

TH: In 1956, there were seven newspapers in Boston, no TV coverage. They showed up and took a couple of pictures. And that was over.

Q: Do you enjoy all this?

TH: Oh yeah. This is my 64th training camp and — 64, I can't believe it. The first one was at the Boston Arena, which now is the basketball place where Northeastern plays [Matthews Arena]. And we had training camps over the years at Babson, when I was playing. We trained in Boston, stayed at the hotel downtown right in Copley Square and so it was way different than it is now. The Celtics have their own facility now with the Red Auerbach Center.

Q: Could you imagine that back in the day?

TH: I'll tell you, Red couldn't imagine. It’s a tremendous tribute to him, of course. We’d train for two weeks and then we'd play over 20 preseason games all throughout New England. For a period of time, every new high school gym that was built, we dedicated it with a game. So we got to tour all over New England and they got to know us. We were the pioneers of the game, bringing basketball to all of the New England states.

Q: What do you think of the 2019-20 Celtics heading into the new season?

TH: Well, the team has got a lot of talent on it. I was very impressed with the rookies in the summer league, the ones that played — and also [Robert] Williams played very effectively at center. We've got two new experienced players [in Kemba Walker and Enes Kanter]. And the whole thing is once again going to boil down to chemistry. When you really have a great team, the question marks revolve around the seventh, eighth, ninth guy. Right now, the question marks revolve around some of the nucleus players and, it's not that they don't have the talent, but it's how they fit together. So, a lot it's going to depend on the interpretation of Brad Stevens and how to utilize them but he's got some talent. It may not show immediately but I think it's going to be a fun team. Marcus Smart puts that competitiveness into everything he does and it's catchy, and the guys that played in the World Cup — I think they're really seasoned players now. So, watch out NBA!

Q: What would be your biggest advice for Brad Stevens this season?

TH: The first thing, to me, is who's gonna start, then you go from there. One of the things that would intrigue me is I always like to put people in unexpected positions. For instance, when I coached a 6-8 center, when 6-8 centers were — nobody had those but us. I see [Gordon] Hayward, potentially, as a power forward and I could imagine if he's close to the peak of his game, I can imagine power forwards trying to stay with him. And it would make it easy on him, I think, defensively and we give [Jayson] Tatum or whoever else is gonna play the other forward spot free rein.

Q: How small could the Celtics go this season?

TH: The smaller you get, the faster you have to get. And you have to be an effective running team. In other words, it's not a sometimes thing. It's on every change of possession, you gotta create a situation where the other team has to really max out their speed and their conditioning. The Celtics were a semi-fast break team last year. I watch the NBA and they told me they want to run and everything else — all I see is, when the other team makes a basket, the center has to walk all the way back, pick up the ball, take it out of bounds, and by the time they inbound the ball to the point guard — just go fast break! Alright? You gotta learn to get the ball quickly and try to beat the retreating defense with the first pass.

Q: Why didn’t it work out for last year’s Celtics?

TH: I thought that the chemistry was destroyed because there was never really a total set lineup. This new era of giving players off the rest and all that stuff — I mean, the whole chemistry got destroyed. If Kyrie [Irving] didn't play, then they played a different way. And when he did play, there was a different way. When they got to the playoffs last year, that first series they played effectively and then the first game against Milwaukee, they just were sensational. But then Milwaukee did to the Celtics what the Celtics were doing to Giannis [Antetokounmpo]. And they took Kyrie out of the game. He really got caught in his own ego at that point. He was trying to really step up and win the game and everybody else then started standing around watching.

Q: Were you surprised that Irving decided not to re-sign in Boston?

TH: Well, everybody jumped all over him last year. He's a great, great player. And during the season I said that there's only two Celtics that played the point guard spot, in my mind, that really understood how to change the game. He read what was going on out there perfectly. The other guy was Bob Cousy, OK? But Kyrie knew when to get rid of the ball and when to shoot the ball and to change the momentum. But he got caught in his ego, his own ego, in that Milwaukee series.

Q: What are your expectations for Tatum and Jaylen Brown this season?

TH: I think Brown is a really solid player now. And if they use him like they did last year, I think he'll be doubly effective. He was coming off the bench, he would be the main man in that [second-unit] attack. They have personnel that can really put the quickness and speed into it, and he gets out in front of that defense, he's going to score a lot of points off the bench. Tatum — If I'm coaching Tatum, what I'm telling Tatum is, I want to see you beat your guy down the floor every single time. Then you have a chance to go against a retreating defense, instead of trying to drive through five guys. He's got the game. He’s a terrific athlete. But he's half-playing college basketball right now.

Q: Who will be the biggest X-factor this year?

TH: Hayward. Hayward has to really be the player that they hoped he would be. I'm led to believe that he looked very good over the course of the summer while training. If that's true, we're going to do all right. If somebody's faking it, and he's not, then then we'll have to find another guy that can carry their team. Kemba Walker is terrific but, down at Charlotte, they expected him to carry the team every single night and I don't think the Celtics are going to ask him to do that. I think he would enjoy playing on a team that's not put on his shoulders every night.

Q: With the big man spot, losing Al Horford and Aron Baynes, are you concerned about this new-look group?

TH: Well, Horford is such an experienced and stable pro. He just was a very competitive guy. We don't have him, we don't have his intelligence on defense. He was the middle linebacker of the team and he knew exactly when to fill a hole and go after the guy, or drop back. He was tremendously intelligent. People that we have right now, Kanter is not that type of player, Williams is untested, and Theis got the possibility to be able to do what Horford was doing but he doesn't have the experience. How you would deal, potentially, with that is to try and get the best of what they do into what you do. For instance, Kanter is a terrific low-post player. He's a wonderful offensive rebounder. Every time I saw him play, boy, he really did some damage to the Celtics. How they play him, how they incorporate him into the offense, if they play him 18 feet and in, that's playing to the strength of his game. If they play him 18 feet and out, you're not going to get the best of what he can give you. So it depends upon how they incorporate him into what they're doing. The other two guys, they're not really offensive weapons but Kanter to me is one of the top 5 low-post players in the league right now.

Q: Sixty-four years of training camp?

TH: Sixty-four years!

Q: How many more are you doing? Can you get to 70?

TH: (Laughs) If I can stand up, who knows?

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