Bobby Valentine will not return as Red Sox manager in 2013, according to a Thursday afternoon news release from the Boston Red Sox.

A search for a new manager will begin immediately.

Executive Vice-President/General Manager Ben Cherington made the announcement and will lead the search.

“No single issue is the reason, and no single individual is to blame," he said. "We’ve been making personnel changes since August, and we will continue to do so as we build a contending club. With an historic number of injuries, Bobby was dealt a difficult hand. He did the best he could under seriously adverse circumstances, and I am thankful to him.”

Valentine's firing comes after the Red Sox finished with a 69-93 record, finishing last in the A.L. East.

“This year’s won-loss record reflects a season of agony,” Red Sox President/CEO Larry Lucchino said in the release. “It begs for changes, some of which have already transpired. More will come. We are determined to fix that which is broken and return the Red Sox to the level of success we have experienced over the past decade.

“Difficult as it is to judge a manager amid a season that had an epidemic of injuries, we feel we need to make changes. Bobby leaves the Red Sox’ manager’s office with our respect, gratitude, and affection. I have no doubt that he will continue to contribute to the game he loves so much and knows so well.”

Red Sox Principal Owner John Henry said, “In our meeting with Bobby today, he handled everything with dignity and class, and it is deeply appreciated. Ultimately, we as owners are responsible for arming our organization with the resources — intellectual, physical, and financial — to return to the levels of competitiveness to which we aspire and to which our fans are accustomed. Our commitment to winning is unwavering. It is a commitment to this team, to this city, and to these fans who have supported us through thick and thin.

“We have confidence in Ben Cherington and the kind of baseball organization he is determined to build.”

“I understand this decision,” said Valentine. “This year in Boston has been an incredible experience for me, but I am as disappointed in the results as are ownership and the great fans of Red Sox Nation.

“It was a privilege to be part of the 100 year anniversary of Fenway Park and an honor to be in uniform with such great players and coaches. My best to the organization. I’m sure next year will be a turnaround year.”