Commissioner Bud Selig appointed Rob Manfred as Major League Baseball's chief operating officer effective immediately the league announced. He will oversee MLB's day-to-day operations. The position had been vacant since Bob DuPuy resigned in September 2010.

"The reorganization of our management team will facilitate an orderly transition and will position Major League Baseball's operations for sustained prosperity well into the future" Selig said in a statement. "I have the utmost confidence in Rob to excel at his expanded duties and to help the industry maintain its extraordinary growth and vitality.

"Rob has tremendous institutional knowledge and first-hand experience with many of our most complex matters including labor revenue sharing competitive balance and the most comprehensive drug program in American professional sports" Selig added. "I am pleased that I will work with him even more closely in the near future."

Manfred had previously served as the league's executive vice president of economics and league affairs. He was responsible for labor relations with the players union as well as human resources. Manfred was a partner in the Labor and Employment Law Section of Morgan Lewis & Bockius LLP in their Washington DC office before joining MLB in 1998.

"I thank Commissioner Selig for placing his faith in me" Manfred said in a statement. "The opportunity to serve the Clubs in this new position is a distinct honor. I have taken great pride in working closely with the Commissioner and supporting the many outstanding initiatives implemented during his tenure. All of us at Major League Baseball look forward to assisting Commissioner Selig during his transition process in preparation for his retirement."