* Selig has overseen historic economic growth in baseball
* Will announce shortly a transition plan for his retirement
Bud Selig, who helped usher in a new era of growth and change in the game of baseball, said on Thursday he will retire as commissioner of Major League Baseball at the end of his current term in January 2015.
Selig, 79, took over the role from Fay Vincent 21 years ago on an interim basis and was unanimously elected MLB's ninth commissioner in mid-1998.
"I am grateful to the owners throughout Major League Baseball for their unwavering support and for allowing me to lead this great institution," Selig, the former owner of the Milwaukee Brewers, said in a statement.
"I thank our players, who give me unlimited enthusiasm about the future of our game. Together we have taken this sport to new heights and have positioned our national pastime to thrive for generations to come."
Among his innovations are interleague play, realignment, adding wild card playoff berths and having the All-Star Game decide home-field advantage for the World Series.
Off the field, Selig presided over some turbulent early years.
Following a long series of strikes and lockouts, labor strife led to the 1994 postseason, including the World Series, being scrubbed, and the use of steroids and other performance enhancing drugs began to make a mockery of the record books.
Under Selig's leadership, a working partnership was struck with the Players Association and together they have brought a 21-year stretch of labor peace to the game and a drug-testing program considered the stiffest among North America's four major professional sports leagues.
During his tenure, Selig has overseen significant economic growth, steering MLB into the realm of new media while implementing fiscal reforms such as revenue sharing and a competitive balance tax on the highest spending clubs.
In 1992, when Selig assumed leadership of the game, total industry revenues were at $1.2 billion. By 2012, revenues had grown more than 600 percent to a record total of $7.5 billion, according to MLB.
"Bud understands how to get things done in this game, and his record speaks for itself," said Hall of Famer Hank Aaron.
"When he retires, he will leave our game in a far better state than when he started. The commissioner has been a marvelous leader for baseball. I am so proud of all that my friend has done for the game we love."
Selig said he would soon announce a transition plan in preparation for his retirement.
"When you step back and view the dramatic transformation Major League Baseball has undergone during Bud Selig's tenure as commissioner, it is truly quite astounding," said White Sox chairman Jerry Reinsdorf.
"A social institution with a long and rich history like baseball is often very resistant and slow to change, yet Commissioner Selig has introduced dramatic, sweeping innovations to improve the game like expanded playoffs, comprehensive drug testing and competitive balance."
Said Hall of Famer Cal Ripken, Jr.: "Bud has done tremendous things for baseball over the last two decades and anyone who knows him understands the passion for and love of the game that he brings to the job.
"His ideas and innovation have vaulted baseball's popularity and his resolve to maintain the game's integrity are things that many of us will remember about his tenure."