BOSTON -- Bill James, widely considered to be the pioneer of advanced baseball statistics, announced on Thursday that he is ending his 17-year run with the Red Sox.

James, who had been in the role of baseball consultant, explained his decision to depart in an essay on his website, billjamesonline.com.

“I leave the Red Sox on the best possible terms. I am still friendly with everyone that I have worked with there, from the owners to the security guards,” wrote James, who added that he would continue to watch most Red Sox games on television.

“Well, maybe not EVERY game; retirement means I don’t have to stay up to watch them play a four-hour game in Seattle ending at 1:30. In exchange for that, next time we win the World Series, I won’t get a ring.”

James leaves the Red Sox with four rings (2004, ’07, ’13 and ’18) accumulated during the club’s 21st century renaissance. The stats maven, who authored countless baseball books over the last several decades, turned 70 earlier this month.

“A 17-year run is a long run,” James said. “I mean, I did the Baseball Abstract for 11 years, and it still defines my career 30-some years later. You look at all of the people who are moving to the sidelines in baseball -- Bruce Bochy, and Ned Yost -- I’m not only older than any of them, I’m much older than any of them.”

In a candid admission, James said that he didn’t do a whole lot to help the Red Sox over the last couple of years.

“I was very fortunate to work in and around Fenway for a couple of decades, but my time has come,” James said. “I’m 70 years old, maximum take-your-Social-Security-dammit age, and, to be honest, I haven’t earned my paycheck with the Red Sox for the last couple of years. I’ve fallen out of step with the organization. The normal flow of work assignments to work products has deteriorated to basically nothing; honestly, I should have left a couple of years ago.”

However, James, who lives in Kansas, made it clear he is not retiring.

“I’m not "retiring"; I’m just retiring from the Red Sox, and I’ll start collecting Social Security, but I still have about 500 work projects that will go forward,” James said. “I have two books written that I need to get published; I have more books that I am writing and more books that I want to write.

“The annual Handbook will be out in a week or so. I have a TV project in the works; I have big dreams. I’m going to get a dog, and a bicycle, and my wife and I will travel, as we always have.

“I’m only 70; I haven’t quite decided whether I want to be remembered as a poet or a playwright or a mystery writer. I will continue to post articles here; in some ways my time will be more available now than it has been. I appreciate you all reading my work, and to the Red Sox: it’s been a blast. Thank you all.”