Just like Ali, Roach has Parkinson's disease -- and while outside of Ecco in NYC, Roach told us the two actually bonded about their conditions when Ali came into his gym about 15 years ago.
"As soon as he started hitting the heavy bag, his tremors went away," Roach said ... "I said we have something in common, because when I do mitts, my tremors go away."
"I think it's more of our comfort zone. We're boxers, we're both very comfortable doing that."
He continued, "I'm a little bit sad that he passed away ... I wonder what I maybe have to look forward to sometimes."
Roach says he's hopeful ... noting they have made tremendous advancements in medicine and science.