Mayweather and Pacquiao can finally settle any questions about their long-standing rivalry this Saturday in Las Vegas.
But this weekend???s winner and loser could be tempted to fight on, with Mayweather hinting at one more lucrative bout in September, while Pacquiao has not talked of retirement.
Khan was previously overlooked by Mayweather, who instead opted for Marcos Maidana, but is still seeking out the two superstars, while Kell Brook emerged as a possible foe for both men after winning a world title in their weight division.
Malignaggi holds both British fighters in high regard, but fears that Mayweather and Pacquiao would look for less risky assignments as they approach the end of their careers.
“I would be honest, I think both guys present too much danger,” he told Sky Sports. “Mayweather and Pacquiao won???t fight them. I don???t see it happening.
“I think if Floyd reaches the crescendo and wins this fight, I think you might see Floyd more so leaning towards retirement, as opposed to Pacquiao. If he wants to fight, he will fight everybody.
“I think if there???s a shot for Amir or any of them, I think it will be Pacquiao, I don???t see Floyd taking on another tough challenge. He has taken on plenty of them and will probably be looking more at going off into the sunset.”
The New Yorker himself pursued a fight against one of the elite pair, but his hopes were shattered by stoppage defeats against Khan and Shawn Porter.
“I came close to fighting them both in 2010,” he said. “There were negotiations at the end of 2009 after my win over Juan Diaz and around Christmas I remember my promoter at the time, Lou Di Bella, on the phone to both sides to see if we were getting the fight.
“They had both called about me, which was interesting, and neither knew the other had called about me. So I told my promoter to get me one of them and I was, honestly, close to getting one of them, but I lost to Amir Khan and that seemed to be the end of the line.
“You know what? I think I’d been close again had I beaten Shawn Porter last year. There were rumours that I would end up in the Mayweather sweepstakes, but Porter was a tough fight and after that I took myself out of the sweepstakes!”