"What if it didn't heal?" Butler told the Journal Sentinel. "Me and the head coach sat down and talked about all the options. I had wanted to go through training camp and see how I did and make the decision then. But I thought about it and what if I go through all that vigorous work and then they flunk me on the physical?"
Butler will formally announce his retirement at a Thursday afternoon press conference at Lambeau Field.
Butler turns 34 on Friday. He recently reduced his salary for this season from $2.25 million to $750,000, plus incentives. It was the third time the four-time Pro Bowler, who has played his entire career in Green Bay, has reworked his contract to help the team. Last year Butler took a $980,000 pay cut. In 1998, he agreed to a base salary of $525,000, a year after signing a five-year extension worth $15 million, including a $4.5 million signing bonus.
Butler needed to play in all 16 games this season to break Bart Starr's franchise record for most appearances. He currently ranks fourth on the team's all-time list, behind Starr (196), Ray Nitschke (190) and Forrest Gregg (187).
Butler said he preferred to go out on his own terms, knowing that it was an injury that forced him to retire rather than the team cutting him, according to the Journal Sentinel. He said he had been prepared to make this decision for several months because of the uncertainty of his shoulder.
He suffered the injury on Nov. 18 against the Atlanta Falcons at Lambeau Field. He underwent surgery a day later.
Fourth-year pro Antuan Edwards, second-year pro Bhawoh Jue, rookie Marques Anderson, and veteran Scott Frost are the leading candidates to replace Butler.