A 47-14 loss to the Washington Redskins on Sunday proved to be the final game in Ryan's two-year stay with the Saints as the franchise look for a solution to their defensive struggles, with senior defensive assistant Dennis Allen stepping up to take the role.
"I'm disappointed for Rob it didn't work out," Payton revealed on his weekly show on WWL Radio.
"I'll tell you one thing now: He's a fantastic staff guy, respected greatly, not only in the locker room but by his peers and we just had to look closely at some point to at least give this an option because the direction we were heading wasn't good.
"We really struggled with substitutions, getting lined up, getting guys on the field and being able to function."
The Saints, who are 4-5 this season, return to action against the Houston Texans on November 29.