For nine seasons, NBA big man Al Horford flourished in his role as the starting center for the Atlanta Hawks.

For the upcoming season, however, hoops fans can catch Horford playing for the away team when he and the Boston Celtics visit the Hawks at Philips Arena in Atlanta on Jan. 13.

The winter matchup will be Horford’s first game back at Philips Arena since his departure from the Hawks during free agency. The 30-year-old NBA veteran signed with the Celtics back in July, just days after Kevin Durant joined the Golden State Warriors. Although Durant’s departure from the Oklahoma City Thunder was the biggest news during free agency, Horford’s name, too, was the cause of a lot of anticipation throughout the sports world.

Until now, Horford had only ever played professional basketball for the Hawks. Atlanta selected him with the third overall pick in the 2007 NBA Draft. At the conclusion of his first season as a pro, he had made the league’s All-Rookie team and helped the Hawks secure a playoff berth. He would go on to help guide the Hawks to eight more playoff appearances during the remainder of his tenure with the team.

Ironically, it was Boston that Horford and the Hawks played in the first round of the playoffs during Horford’s rookie season. During that series, the Hawks famously impressed, taking the heavily favored Celtics to seven games before losing to them in the final game on the Celtics’ home floor. Boston would go on to win the NBA title that season.

In January, fans will want to pay close attention to the match-up between Horford and the opposing team’s new center: Dwight Howard. Like Horford, Howard is a 30-year-old veteran who signed with a new team this off-season, but unlike Horford, however, Howard’s lackluster efforts on the court in recent years have tainted his status as one of the league’s premier players. Now that Howard has been given a fresh start with his hometown team, it is anticipated that he will be reinvigorated and return to form while playing for Atlanta. If Howard does return to form, his expected battle with Horford next season should be one to look forward to.

Celtics Head Coach, Brad Stevens has a lot to work now that the franchise has added Horford. Horford joins a playoff contender that has qualified for the postseason three times since the dismantling of its Big 3, which consisted of Paul Pierce, Kevin Garnett and Ray Allen. With the absence of the Big 3, Horford adds veteran leadership to a club loaded with much younger talent, such as first-round draft pick Jaylen Brown and point guards Isaiah Thomas and Marcus Smart.

The Hawks will be relying on the aforementioned Howard, as well as All-Star and seasoned veteran Paul Millsap, to lead them to victory next season. Horford’s absence might take Hawks Head Coach, Mike Budenholzer and the rest of the team some getting used to.

Horford’s presence might be missed in Atlanta, but he is sure to give his best shot against his former team when the Celtics come to town on Jan. 13. Tip-off for the game is set for 8 p.m. EST.