The Hawks needed a wing player with size.

Enter Thabo Sefolosha.

The team agreed to a three-year, $12 million contract with the unrestricted free-agent guard Thursday, according to a person familiar with the situation. In Sefolosha, the Hawks nabbed a starter from the Western Conference power Thunder. The Hawks cannot sign Sefolosha until the NBA’s moratorium on free-agent signings concludes July 10.

“I definitely got a big smile on my face right now,” Sefolosha told the Oklahoman newspaper.

Sefolosha (6-foot-7, 222 pounds) was a 2006 first-round draft pick (No. 13 overall) and has played eight seasons with the Bulls and Thunder. He has been a starter for 5-1/2 seasons since joining the Thunder.

The signing fills a void for the Hawks, who struggled when either DeMarre Carroll or Kyle Korver was out of the lineup. The Hawks were 1-8 without Carroll and 1-10 without Korver last season. They were 0-2 without both. Sefolosha also gives the Hawks another strong defender.

Sefolosha, a native of Switzerland, averaged 6.3 points, 3.6 rebounds and 1.5 assists in 26.0 minutes for the Thunder last season. He shot 31.6 percent (48 of 152) from 3-point range. For his career, he has averaged 5.8 points, 3.7 rebounds and 1.5 assists in 23.4 minutes. He is a career 34.8 percent 3-point shooter. Sefolosha started 367 of the 368 games he played for the Thunder. He should fit the ball-movement offensive system of coach Mike Budenholzer.

Sefolosha told the Oklahoman that Budenholzer reached out to his representatives early in free agency. He said the two met in Washington, D.C., to discuss his role with the team.

“We had a very good meeting where we could talk a little bit about both of our visions and everything,” Sefolosha told the newspaper. “And it made sense for them to pursue trying to get me to the team. And it definitely made sense once I got the offer for me to go there.”

Sefolosha, who visited the Wizards on Wednesday, made $3.9 million with the Thunder in the final year of his contract. He had a difficult exit from Oklahoma City. Sefolosha was left out of the starting lineup, in favor of Caron Butler, in Game 6 of the first-round playoff series against the Grizzlies. He played sparingly in the next two series against the Clippers and eventual NBA champion Spurs.

Kevin Durant, the reigning league MVP, praised his Thunder teammate via social media following the news. He tweeted: “Congrats @ThaboSefolosha! Thanks for all the hard work u put in while in a thunder uniform, good luck.”

Once the Hawks waive John Salmons, acquired in a trade last week, they will be about $11.5 million under the salary cap for additional signings, should they choose. They are still believed to be interested in forward Luol Deng, who only recently returned to the United States to begin meeting with several reported suitors.