Horford here in a Celtics uniform will be weird

Let’s face it: To see Al Horford in a Celtics uniform is going to be weird.

Odd not just for Hawks fans, but for former coaches and teammates and Horford himself.

After nine seasons at the core of the Hawks organization, Horford makes his first trip to Atlanta with the Celtics on Friday, six months after he signed with the Celtics as an unrestricted free agent last summer when he and his first team could not come to terms.

“It’s very, very weird for me,” Horford said in an interview with The Atlanta Journal-Constitution Thursday. “I’m really close with those guys in the locker room. It’s just very different. There is no way else I can put it.”

The Hawks drafted Horford No. 3 overall in 2007 and he led the team to the playoffs every year upon arriving as a 21-year old from Florida. He grew to become a four-time All-Star. He played 578 games, despite having lost nearly two seasons to two separate torn pectoral muscles, and averaged 14.3 points and 8.9 rebounds. He ascended to the top 10 in many of the franchise’s all-time records, including No. 2 in field goal percentage (.535).

Horford said he has only recently thought about the return trip. He admits to watching the out-of-town scores but that now, it’s starting to get real. He said he has not thought about the reception he will receive from Hawks fans, both those cheer him for a long and distinguished career or boo him as a player who moved on.

“I have so much love for the Hawks fans,” Horford said. “They really embraced me from the very first day I got there. I’ve spent some good years there. Regardless of what the reception is, I’m always going to be grateful to them.”

About 63 percent of respondents to a recent Atlanta Journal-Constitution poll on Thursday indicated they would cheer for him.

Horford said his welcome to Boston moment — he called it surreal — came when he was driving to his first game at Boston’s TD Garden, a routine acted out so many years in Atlanta suddenly replaced by a different city and team.

Horford was part of the established roster when Mike Budenholzer arrived four seasons ago. The young first-time coach came to Atlanta with a new system and a new style of play. Having a talent with the stature of Horford accept him was crucial to the continued success of the team and Horford was also a stabilizing influence during controversy that engulfed the team the next season.

“Al has such a presence,” Budenholzer said. “For him to welcome me and welcome a different style of playing, a different system, I am very grateful to him. …

“When your best players are buying in and willing to do anything that the coach — in this case, me — is asking, everyone else tends to fall in line. He was one of those guys who helped us establish a culture and a way of playing. He’s moved on, we’ve moved on, I think, with a ton of respect for each other.”

The Hawks are planning a video tribute to Horford to be shown during the game.

It was a four-year, $113 million contract offer that drew Horford to Boston after the Hawks could not reach agreement on length of contract or financial terms.

Horford played center for the Hawks even though he preferred to play power forward. He continued to accept his role, although under Budenholzer the center and power forward were nearly interchangeable positions. He became a legitimate spread-5, spacing the floor and becoming a threat from the 3-point range. In his last season with the Hawks, Horford was 88 of 256 from 3-point range. In his previous eight seasons, he was a combined 21 of 65 from long range. Horford continued to have one of the best mid-range jumpers for a big man in the NBA.

The offensive role has changed for Horford with the Celtics. He plays primarily power forward and on the perimeter. He is already 44 of 130 (.339) from 3-point range this season. Celtics coach Brad Stevens even drew up a final-second play for Horford last week, a corner 3-pointer that was the game-winner against the 76ers.

“Very different, completely different,” Horford said of his new system. “I’m playing a lot on the perimeter. My shot is coming from every different way. It’s been an adjustment. It’s been a process that I’m still getting comfortable in the system. … With the Hawks it was more pick-and-roll and pick-and-pop.”

In addition to the return of Horford, there is something on the line in the game. The Celtics are third and the Hawks are fourth in the Eastern Conference, separated by just 1-1/2 games. Once the game starts, that will be the focus. Still, before the opening tip, Horford dressed in green will take some getting used to.

“As a fan of basketball myself, it’s weird to see Al Horford in a Celtics jersey,” Paul Millsap said.