Chuck Armstrong, who handled both those roles, will retire from the club on Jan. 31 after 28 years with the franchise. Mather and Aylward will begin their new jobs on Feb. 1.
Armstrong was the Mariners' president and chief operating officer from 1983-89 and 1992 to the present, and has chaired the board of directors of NW Sports Net since the Mariners acquired majority interest in the regional sports network last April.
Both Mather and Aylward will report to Mariners chief executive officer Howard Lincoln.
"Kevin and Bob have been very valuable executives of the Mariners," Lincoln said. "They are both extremely talented, experienced and well-qualified to lead our organization into the future. There will be a seamless transition as Chuck begins his retirement one week from today."
Mather, 51, has been overseeing the club's accounting and financial reporting, ticket services, concessions and day-to-day operations of Safeco Field. He was VP of finance of the Minnesota Twins from 1989-96 before being hired by the Mariners.
"Our fans, first and foremost, are our focus, and we understand what they want most -- a championship team," Mather said. "I am looking forward to supporting [general manager] Jack Zduriencik as he continues to lead the baseball operation and builds the Mariners both for 2014 and for future seasons. At the same time, our commitment to this community and this region will remain a top priority. This is a tremendous opportunity, and I'm excited about the Mariners' future."
A native of Madison, Wis., Mather is a 1984 graduate of the University of Wisconsin, where he received a degree in accounting and risk/insurance prior to taking a job with an accounting firm for four years.
Mather was hired by the Mariners as VP of finance and administration in July 1996, then promoted to an executive vice president's position in December 1999.
"Kevin's experience in the game of baseball has prepared him well for this position," Lincoln said. "He is highly thought of around Major League Baseball and in this community. He will work closely with me to make sure Jack Zduriencik has the resources he needs to build winning teams. Jack remains the leader of the baseball side of our organization."
Aylward, 60, joined the Mariners in 1997 as VP of business and sales. After overseeing all business aspects of the transition from the Kingdome to Safeco Field, he was promoted to executive VP of business operations in December 1999. Aylward has been a driving force in the Mariners' efforts in corporate sponsorships, advertising and ticket sales, marketing, broadcasting and communications.
"I love the game of baseball, this community and Mariners baseball," Aylward said. "The club's business operations and ROOT Sports are integral to the future of the franchise, and I appreciate the opportunity to direct both groups."
Aylward, a native of Pace, Miss., was with the Orioles from 1976-94, rising through the ranks to the position of VP of business affairs while helping with the design, construction and move to Oriole Park at Camden Yards in 1993, which started the movement to retro ballparks in MLB.
"The Mariners own a majority stake in ROOT Sports Northwest, an extremely important part of our franchise's future," Lincoln said. "Bob was instrumental in the Mariners' acquisition of the regional sports network and will lead the network into the future. He will continue in his position as the Mariners EVP of business operations, and he is one of the very best in baseball."