Ainsley has been with the company for 27 years. He was the one on the scene this year when New York executives stayed away during the height of the drama with newspaper unions after the company threatened the Globe‘s closure unless $20 million in contract changes were made. He aslo serves on the company’s executive committee; Mayer is not mentioned as the successor for that spot.

Update: Ainsley and NYTCo CEO Janet Robinson described the changes in separate memos to the staff that have been posted by Boston.com. Robinson praised Ainsley for “guiding The Boston Globe through a substantial economic downturn and dramatic technological change.” Mayer, she writes, “has a proven track record with broad experience in circulation, marketing, product distribution, production and information technology.” He’s proactive, collaborative, can handle complex projects, and more, But this may be the central point: “All of this will be essential as the Globe moves into the future and becomes an even more effective multiplatform enterprise.”

Translation: Ainsley was the person to see the Globe through the cost cutting, the uncertainty of the past year and he may well have stuck around through a sale until the new owners were in place; Mayer is the exec for a cross-platform future.