Red Sox play by play man Don Orsillo, a 15 year veteran in the NESN booth, will not be returning next spring, with the club opting for ESPN fixture/NESN radio announcer Dave O’Brien as Orsillo’s replacement.

Though I certainly don’t catch every Red Sox telecast,I’m baffled how they cut Orsillo loose. A great TV broadcast duo or trio can make you feel warmly about a club even when everything else in the organization sucks like crazy (see NY Mets, 2009-2014) and you cannot deny Orillo’s chemistry with Jerry Remy (as the above clip from 2007 illustrates). But as The Boston Globe’s Chad Finn writes, while Orsillo’s firing “is disheartening for those who appreciate his polished and often humorous approach…it is not a shock to those in the industry.”

It was speculated on “Dennis and Callahan” that the Red Sox ratings, which have dipped to 3s and 4s in a disappointing season, were a reason for moving on from Orsillo. That may be a factor, but it’s not the main reason.

According to industry sources, Orsillo was never a favorite of Joseph Maar, NESN’s vice president of programming and production/executive producer who arrived at the network in July 2012. Last year, Maar implemented the policy of having its broadcasters — Orsillo and analyst Jerry Remy, in this case — take in-season breaks.

A NESN spokesman said last year that the policy was implemented to keep broadcasters fresh, but it also serves another purpose: A week off during the season for its broadcasters means they must make up the week of work outside of baseball season, which is unusual given their grueling schedule from April through at least September. Orsillo, known as a team player among his colleagues at NESN, was resistant to this approach.