Renegotiation talks between the Colts and Harrison were unsuccessful during the weekend, and he has asked the team for his release.
"There was nothing confrontational about this, no protracted negotiations," Harrison's agent, Tom Condon, told ESPN's Chris Mortensen on Monday. "We knew where things were at so we asked for his release."
Colts president Bill Polian told reporters Sunday at the NFL's annual scouting combine that the team was trying to rework Harrison's deal to lower the receiver's salary-cap number from approximately $13.4 million, the highest number of any wideout in the NFL. Harrison is scheduled to make $9 million in 2009.
Since Harrison and the Colts can't seem to find common ground on redoing his contract, the only other options for the team would be releasing Harrison or keeping him at his cap number.
Harrison has been one of the Colts' most identifiable players since their move to Indianapolis. He ranks No. 2 in the NFL in career receptions (1,102) and holds all of the franchise's major career and season receiving records.
He is also 36 years old, coming off one of the least productive seasons of his career -- he also missed all but five games in 2007 -- and with the Colts in a salary-cap crunch, Polian may not be able to keep Harrison at his current price.
Next year's cap is expected to be $123 million.
"The new cap rules, that's not something we planned for," Polian said. "As a result, we have some issues with veterans, including Marvin. Hopefully, we'll find a way to work through that. I don't know if we will, but we hope to."
Earlier this week, Colts head coach Jim Caldwell said he was hopeful Harrison would be able to return to the team, but it was apparent the franchise is unwilling to have him on the team with a $13.4 million cap number.
Since being drafted by the Colts in 1996, Harrison has been a model of consistency.
He's made eight Pro Bowls and won a Super Bowl ring. His 14,550 yards rank fourth on the NFL's career list and he's No. 5 with 128 TD catches. Harrison and Peyton Manning also teamed to produce the most proficient passing tandem in league history.
But Manning has increasingly thrown more passes to Reggie Wayne, who has made the past three Pro Bowls, while Anthony Gonzalez, Indy's first-round draft pick in 2007, has made a push for more playing time.
Polian and Caldwell have repeatedly said they do not believe Harrison's skills are deteriorating.
"What I saw is a guy who is as quick as he's been, with the same hands and he has the ability he's always had," Caldwell said Thursday.
Philadelphia police also believe one of Harrison's guns was used in a shooting in his hometown last summer. No charges were filed against Harrison, and the man who made the accusation is now headed to trial for lying to police.
Harrison isn't the only veteran the Colts could lose this week.
Polian said Sunday that he had made an offer to three-time Pro Bowl center Jeff Saturday and Saturday was "mulling it over."
Saturday, however, told The Associated Press later that he has discussed it with his wife and has decided to become a free agent. Players can begin signing with other teams on Friday.
"I think I made it very clear that I wanted to stay in Indy, that's where my wife and family wanted to stay, and I wanted to retire here," he said. "But I'm moving into free agency because my wife and I decided this is what is best for our family, though I've not completely ruled out playing for the Colts."
Saturday has started 138 games in nine seasons and is responsible for making blocking calls along the line.
Those two, along with Manning and punter Hunter Smith, are the longest-tenured players on the Colts' roster. Smith's agent, Thomas Mills, has said Smith also does not expect to be re-signed by the Colts before Friday.
Saturday said he was surprised by the offer and has made his decision.
"After Kelvin [Hayden] was done, Bill called and we met and that's when he came with the offer," Saturday said. "We discussed it"
Saturday would not discuss details of the Colts' offer or characterize the contents.
The problem for Indianapolis is salary-cap space.
On Thursday, the Colts signed Hayden, a corrnerback, to a new five-year, $43 million deal. That means since 2004, Manning, Harrison, Wayne, Dwight Freeney, Robert Mathis, Ryan Diem, Bob Sanders, Dallas Clark and Ryan Lilja have all signed contracts worth at least $19 million.
Polian does not believe those deals have put Indy in the money pinch; the new salary-cap rules have.
Clearly, though, Harrison's six-year $66 million deal, with $22 million in bonuses, signed in December 2004 is now proving too costly and if Harrison doesn't accept a pay cut, he may be looking for work in another city.
"I don't want to characterize the discussions," Polian said of the negotiations with Harrison. "But we are impacted by the salary cap for the first time in 11 years."
Information from The Associated Press was used in this report.