PORTLAND — Marie Bourque-Namer watched pregame warm-ups from her usual seat in the Portland Expo — the back row behind the Maine Red Claws’ bench. On either side of her sat her young grandchildren, Alex and Hailey, both veterans of Red Claws games, like their grandmother, but still wide-eyed over the action taking place below.

“It’s a big game tonight,” said Bourque-Namer, a Bath resident and Red Claws season-ticket holder. “We could easily get knocked out of second place if we don’t pay attention to business.”

Down on the Expo’s parquet basketball court, the Red Claws are preparing for a late Sunday afternoon showdown with the Sioux Falls Skyforce, who sit just a half-game behind Maine in the NBA Development League’s East Conference. Along the edges of the new floor, a sellout crowd is filing to plastic bleacher seats for a 5 p.m. tip-off.

Bourque-Namer pulls out a gray Spaudling basketball splashed with autographs from various members of the Red Claws, most of whom have moved on — Alexis Ajinca, Will Blaylock, Noel Felix,  Among the signatures, only Billy Thomas, Darnell Lazare and Anthony Terrell, who is injured, remain from the roster that started the season in late November.

“Anthony taught Alex how to write an autograph,” Bourque-Namer said. “He said when you’re writing an autograph, make sure they can read not just the number, but the name.”

The Red Claws have had a lot of names on their roster this year, yet the number of fans flocking to the venerable Expo continues to escalate at a rate that even the people who brought the NBA D-League to Maine didn’t expect when they were awarded the franchise 13 months ago.

“We weren’t exactly sure what we were getting ourselves into, but we were convinced that, if done right, minor league basketball would be very successful here in Maine,” Red Claws president, general manager and part-owner Jon Jennings said. “What we’ve seen is a very overwhelming response to what we’ve tried to do.”

The Red Claws have sold out every game so far this season, and expect to sell out the remainder of their 24-game regular-season home schedule. Capacity at the renovated Expo is 3,045. Less than half of that, a little over 1,400, consists of season-ticket holders.

Bourque-Namer bought three season tickets at $10 per game, a total of $720 for her back-row seats (“I could have bought a front row seat for myself, but that wouldn’t be any fun,” she said.) She has been to every game with either her children and/or grandchildren. They always ask her to bring them back for another game.

“I just can’t say how much I like it,” she said. “Once you come, I think you get hooked.”

“They really take good care of the season-ticket holders,” she added.

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Being a season-ticket holder certainly has its perks, whether it’s spending a couple of hours frolicking on the parquet after a game, being a ball boy for the Red Claws or participating in a “dunk contest” the team holds for young children during timeouts.

Not only have Bourque-Namer and her family met the players, they have gotten to know many of them. They have even maintained contact when some of the players have moved on, such as Ajinca, a 7-foot center who was recalled by the Charlotte Bobcats.

“He Facebooks us all the time,” Bourque-Namer said.

“The only thing that’s been hard for us is all the change in players,” she added. “But we understand it.”

Change is a fact of life in the NBA D-League. For the game against Sioux Falls, the Red Claws suited up the 14th and 15th different additions to their roster this season — Kurt Looby, whom they had just acquired in a trade, and Marcus Landry, who was assigned from the Boston Celtics.

Maine is affiliated with both the Celtics and the Bobcats and has sent four players back to those NBA teams — Ajinca to Charlotte and Bill Walker, J.R. Giddens and Lester Hudson to Boston. A fifth player, Mario West, was signed by the Atlanta Hawks. Only one other team in the D-League has sent more players to the NBA.

Jennings doesn’t see the roster turnover as being unusually high for the Development League. But 14 different Red Claws have led the team in scoring in a game. Thomas, a league veteran and the team captain, said it is hard to keep the team chemistry with that much turnover.

“I don’t think I’ve ever seen a situation where you start with a core of 10 guys and then, before the season’s even over, you have only two guys left off of that team. That’s unheard of,” Thomas said. “I don’t know if you chalk it up to being an expansion team, but it’s definitely tough for the players to make adjustments to that.”

Red Claws coach Austin Ainge, son of Celtics general manager Danny Ainge, said getting so many new players to blend into the team takes patience from the players and coaches.

“It depends on the guy,” he said, “but it’s hard at this point in the season because a lot of teams are clicking so well and playing so well that if you have to take a half-step back with new guys, it can be hard.”

Team atmosphere

Yet despite all the new faces, the product has not suffered on or off the court. Despite losing to Sioux Falls, 99-98, on a buzzer-beater, the Red Claws regained second place in their division this week and are close to becoming just the third expansion team in league history to reach the playoffs. Jennings, a former assistant coach and scouting director for the Celtics, said the moves that the team has made were meant to do more than just keep the Claws competitive.

“I think we’ve got one of the best teams in the league,” Jennings said, citing the individual talent on the roster. “Morris Almond, Maurice Ager, Russell Robinson, you go up and down the list of guys that are NBA caliber talent. I grew up working for a guy who didn’t believe in excuses, Red Auerbach, so I don’t accept a lot of excuses. It is what it is, so guys have got to step up, and that includes the coaches, and get the job done.”

The Red Claws have also been getting the job done in terms of tickets sales. Like the Portland Sea Dogs next door, the Red Claws have benefited from their Boston ties and from being an affordable venue for family entertainment. And despite being an expansion team, establishing an identity in a city with three minor league teams has not been a problem, according to Red Claws chairman and co-owner, Bill Ryan Jr.

“Minor league sports isn’t about the individual players usually. It’s more about the atmosphere of the team,” he said.

Contributing to the atmosphere, Ryan said, is the Expo, which is the second smallest arena in the D-League.

“I’ve been to five or six different D-League buildings this year that are 7,000 seats, 8,000 seats,” said the Oxford Plains Speedway owner, “and even if you have 3,000 or 4,000 people in there, it doesn’t have the same atmosphere.”

“I think it’s perfect for our league,” Thomas said of the Expo. “Guys come in here and they see it full and they see the fans right on top of you and it gives us a definite home-court advantage.”

While the Portland Pirates are considering moving because they are dissatisfied with the economic viability of the Cumberland County Civic Center, the Red Claws are satisfied with the Expo, which underwent $300,000 in renovations prior to the season.

Making the best use of the facility took some time, though.

“We did know moving into the Expo that there would be challenges. We certainly don’t regret moving into the Expo. We think that was one of our better decisions,” Jennings said. “But we do need to figure out how to make the seating more comfortable and so forth. And we’re constantly monitoring and soliciting advice from our fans as to how we can improve the in-game experience.”

“They ask us periodically what they did well and what they didn’t do well,” Bourque-Namer said. “As changes happened sometimes we’d find out about it a couple of days later or from somebody else, and so we told them they needed to communicate the change early on. And they’ve done it.”

Not a typical expansion team

The Red Claws have reacted to most of the typical first-year issues of an expansion franchise like a point guard running the middle of a fast break — on the fly. But in many ways, they no longer resemble an expansion franchise, They are already second in the league “and closing fast” in corporate sponsorship, according to Jennings, who declined to reveal their revenues. The recently-launched season-ticket renewal campaign is going “extremely well,” he said.

The players have noticed the way the franchise is quickly entrenching itself in Portland.

“There was a buzz around the city about the team, and I think it’s fair to say that as an expansion team, we’ve far exceeded expectations,” Thomas said. “As far as the relationship with the fans, it hasn’t been like an expansion year. It’s been like we’ve been here for at least five years.”

Jennings chalks it up to fans’ basketball knowledge and the promotion efforts the team and players have made. The Red Claws, whose games are broadcast on radio and, periodically, on television, held preseason scrimmages and exhibition games in Auburn and Augusta. The team has also been involved in numerous community and charitable events. Last week, the players and coaching staff participated in various community events reaching 1,200 children, according to Jennings.

“The players have been extremely cooperative this season in getting out and making a positive impact in the various communities around Maine,” Jennings said. “We want them to know and the fans to know it’s not just about a basketball game and coming to the Expo 24 nights out of the year.”

He added that the team will do whatever it takes to make sure they keep coming.

“The one thing about us is we’re never satisfied,” he said. “So we want to get better in every aspect.”