The GM hadn't just criticized his defense and focus in a radio interview during the 2010 season, he'd embarrassed him. Or at least that's how Kemp saw it.
"He'd say to me, 'I can't live like this,'" Kemp's agent, Dave Stewart, recalled on Friday. "'Every time I come to the ballpark I sit here and I'm pissed off at him and it's taking away from what I want to do.'"
Colletti could feel Kemp's animosity. And though he was still frustrated with his young star's performance on the field, he knew he needed to make it right. Kemp was too good of a player to struggle like this. His future was too important to the Dodgers' future to let bad feelings affect things so deeply.
A few weeks after the incident Colletti and Kemp had a heart-to-heart conversation that led to several more heart-to-heart conversations over the next few months. It changed everything.
"Our relationship maybe took a quarter step back that day, but as soon as we had a conversation, it took a huge leap forward and it continues to leap forward," Colletti said.
"We had as solid and as true of a conversation as two people can have. From that day on, he knew where I was at and I knew where he was at and we decided we were better off being together than apart.
"I let him know: 'If we get your full effort, that's all we need. However it goes after that, it's how it goes. But if we get your full effort, I'll be the biggest advocate you'll ever see.'"
In the offseason, Colletti overtly showed that support by convincing Stewart's close friend Davey Lopes to join the team as a first-base coach. He also did not bring back bench coach Bob Schaeffer and third-base coach Larry Bowa, both of whom had run-ins with Kemp on several occasions.
"As 2010 moved on, I thought that I needed to add more foundation for him," Colletti said simply.
Kemp went out and had a season for the ages in 2011, leading the National League in home runs (39) and RBIs (126) and finishing third in batting average (.324).
Colletti really made good on his end of the original promise Friday afternoon as the Dodgers signed Kemp to a record eight-year, $160 million contract extension that will keep him with the club until 2019. It is the richest contract in Dodgers history.
"They found a way to meet and they squashed it," Stewart said. "Ned was persistent in building their relationship back up. Even to the point where he admitted he didn't handle that situation as he should have. I think once it went in that direction, then everything flowed."
If only the story ended there.
But as so many things surrounding the Dodgers have these days, there is a troubling subtext to it that's hard to ignore.
It is more than a little strange that on the same day the Dodgers signed Kemp to the largest contract in National League history, Colletti acknowledged that the team's payroll will be smaller in 2012 than it was in 2011.
"The payroll is probably going to be lower than it was a year ago," Colletti said glumly. "That's what I've been told."
Told? By whom?
Embattled owner Frank McCourt is still in control of the club's day-to-day operations for as long as he owns the team. He has even more say now that he has an agreement with Major League Baseball on the conditions of that sale.
In other words, the 2012 payroll is McCourt's call, not baseball's.
The other day, when word of Kemp's new contract extension became public, I wrote that fans have to consider the possibility that McCourt green-lighted this deal in order to pave the way for a more dignified exit from the club.
It would seem that locking up Kemp to a long-term deal adds to the value of the franchise. But that's just a guess at this point. The market will determine that once the bidders in the auction get serious.
Now I'm not so sure of the purity of McCourt's intentions with this deal.
Locking up Kemp is the right thing to do for this franchise. It also happens to give McCourt considerable cover to cut the Dodgers' payroll this winter as he readies the club to be sold and fetch its highest price.
Where this really gets interesting is when you listen closely to Kemp, Colletti and Stewart.
Stewart said Friday that Kemp told him he wanted to get this deal done as soon as possible so the team could make a run at the top free agents on the market, most notably Kemp's friend Prince Fielder. Baseball's winter meetings are Dec. 5-8 in Dallas.
He also explained that Kemp agreed to take less in the first year of the deal to give the team more flexibility this winter.
"The ballclub needed flexibility, Ned was clear in explaining that," Stewart said. "What was important really was the overall package for Matt.
"He's an unselfish kid. It's been his thought all along that he'd like to get somebody else there that they can put in the lineup that can help him, help the team win."
That all sounds wonderful until you listen again to Colletti, who said Friday that he "didn't know if it was going to be possible" to re-sign pitcher Hiroki Kuroda, and noted earlier in the week that the team wasn't likely to pursue free agents of Fielder's class and price range.
"Unless something changes, I think it looks less realistic," Colletti said. "I think we have to figure out other ways to produce runs."
There's no way Stewart and Kemp could have missed Colletti's previous comments or been unaware of the Dodgers' financial issues as they go through this sale process. Remember, Colletti and Kemp are close now. They've repaired their relationship and talk often. Colletti and Stewart go back 30 years.
So you have to wonder whether something else is going on here.
Could Kemp and Stewart be ratcheting up the pressure on McCourt to give Colletti the chance to make a realistic run at Fielder? Or at least not be hamstrung with a budget smaller than last season's?
Kemp has said often that he and McCourt are friends, that the owner has always treated him well and acted with honor in their dealings. He showed up to support McCourt on Monday at the dedication of a Dodgers Dream Field in Compton where McCourt made his first public statements since agreeing to sell the team.
Kemp spoke convincingly about McCourt's character and the purity of his motives.
But he's also spoken convincingly about becoming the leader of this franchise and wanting to win a World Series.
His actions have backed that up and then some.
"I want us to go out and get other people to help us to be even better," Kemp said. "Whether it's another bat or another pitcher, we can all use great players. If I can help us do that, I'll do it."
Just by saying that out loud, he is helping.
Now he has to hope McCourt gets the message.
Ramona Shelburne is a columnist and reporter for ESPNLA.com.