"We all know that nothing lasts forever," Manning said. "Times change, circumstances change, and that's the reality of playing in the NFL."
Manning and Irsay each paused frequently, fighting tears and their voices shaking, as they appeared together at a news conference at the Colts' team complex. It was an unusual and awkward scene, two men whose NFL lives have been so closely intertwined, standing side-by-side in jackets and ties as they told the world they were splitting up.
"This has not been easy for Jim," Manning said, "and this has certainly not been easy for me."
The 35-year-old Manning will become a free agent, and is expected to generate interest from a half-dozen or so NFL clubs, provided he's healthy. Manning is coming off a series of operations to his neck and missed all of last season when his team's record, not coincidentally, plummeted to 2-14.
Indianapolis needed to cut him this week to avoid paying him a $28 million bonus, although both Irsay and Manning insisted the decision was not really about money. The Colts are widely expected to begin moving on by taking Stanford quarterback Andrew Luck with the No. 1 overall pick in April's draft.
Irsay repeatedly used the word "rebuilding" and acknowledged: "We're definitely a few years away."
Manning won't retire and hopes to be playing in the NFL at the start of next season.
Still, he said Wednesday: "I'll always be a Colt. I always will be. That'll never change."
The announcement was made in a room at the Colts' complex normally reserved for celebratory news conferences, such as the hiring of a new coach or general manager -- two other major steps Irsay took recently. The room is lined with banners honoring some of the team's greatest stars, including, of course, Manning himself, flanked by Pro Football Hall of Famer members Eric Dickerson and John Mackey.
Clearly, this was not an easy goodbye for Manning. He even got choked up while discussing all of the Colts employees he'll no longer be around, pausing to collect himself while noting: "We've got the greatest equipment guys in the world."
Manning forever will be thought of around these parts as No. 18, the quarterback who led the Colts to an NFL championship, barking out signals while waving his arms at the line of scrimmage to change a play after reading the defense -- something he did as well as any QB.
He'll be remembered, too, for his record four MVP awards, his 50,000 yards passing and his 200 consecutive starts. Most of all, Manning will be the guy in the horseshoe helmet who turned around a franchise and transformed a basketball-loving city into a football hotbed that hosted the Super Bowl a month ago.
And during that Super Bowl week, the hottest topic of conversation was Peyton Manning, not his younger brother Eli, who wound up leading the New York Giants to the title.
Arizona, Miami, Tennessee, Washington and the New York Jets all have been rumored as possible destinations now; Manning's former offensive coordinator in Indianapolis, Tom Moore, worked for the Jets as a consultant last season.
"There will be no other Peyton Manning," Irsay said, adding that he hoped Wednesday's joint appearance would serve to "honor incredible memories and incredible things that he's done for the franchise, for the city, for the state."
This marks the end of a remarkably successful marriage between a player and team.
After being a No. 1 draft pick himself, Manning started every meaningful game for 13 seasons in Indianapolis -- 227 in a row, including the playoffs -- and took the Colts from perennial also-ran to one of the NFL's model franchises and the 2007 Super Bowl title.
In the two decades predating his arrival, the Colts won 116 games, one division title and made the playoffs three times. With Manning taking snaps, the Colts have won 150 games, eight division titles, two AFC championships and the franchise's first league championship since moving from Baltimore in 1984.
Indianapolis broke the NFL record for most regular-season wins in a decade (115), and tied Dallas' mark for most consecutive playoff appearances (nine).
Manning is one of just four players to reach 50,000 yards passing, one of three with more than 350 TD tosses, and one of two quarterbacks with more than 200 starts in a row. He broke all of the franchise's major career passing records, previously held by Hall of Fame quarterback John Unitas.
In 2009, Manning led the Colts to the cusp of NFL history with a 14-0 start, fueling talk of an unbeaten season.
But it has been mostly bad news ever since.
The Colts pulled their starters against the Jets and lost the final two games that season. Indy then wound up losing to New Orleans in the Super Bowl. During the offseason, Manning had the first of his neck operations.
Then, after making an early playoff exit in the 2010 season, Manning underwent another neck surgery to repair a damaged nerve that was causing weakness in his throwing arm.
When the nerve did not heal as quickly as expected, Manning had two vertebrae fused in September, an operation that forced him to miss a game for the first time in his NFL career. There are still questions about the strength of Manning's arm.
But given all that he's accomplished, there are sure to be new suitors.
"I'm throwing it pretty well. I've still got some work to do; I've got some progress to make," Manning said. "But I've come a long way. I've really worked hard. I can't tell you the hours and the time I've put in."