If it was intended as a shot at Dan, it's pretty low. If Marino would have played on the same team as Bradshaw, those Steelers would have won at LEAST 6 Super Bowls. Those two down years they didn't win (Super Bowls XI and XII) would never have happened. Same thing if Marino would have played on those 49er teams in the 80's. IMO, There is not much of adebate as to who is the best ever. Elway is the only other QB that is even close to Dan. It's unfortunate Dan never had a team anywhere near the caliber of the 70's Steelers or 80's 49ers. If he had, the would be NO debate by anybody if Marino was the best ever. BTW, those Steeler teams sometimes won in spite of Bradshaw (he was similar to Favre with the frequency of interceptions. Yes, I know passing ruels were different then but the argument is valid). But I still think Bradshaw was a better QB than Joe Montana. Montana (in many ways) was a system QB. Even Bill walsh said that Montana would probably have ended up playing in Canada had he not ended up with the 49ers and the west coast offense.
Finally as an aside, Pittsburgh sportscaster Bill Hillgrove saw that Steelers dynasty and he saw Bradshaw. On an NFL Network countdown of the greatest draft steals of all time, he said without qualification, "Dan Marino is the best quarterback who ever put on a uniform". This wasn't the only person to knock Bradshaw. A reporter on ESPN (Sportscentury on Peyton Manning) said that if Archie Manning had played for the Steelers and Bradshaw had played for the Saints, you would still see Archie's name plastered everywhere and he would be revered as an all-time great. Nobody would know or care about Bradhsaw.
Marino loved Bradshaw growing up. Bradshaw should feel honored to have someone as great as Marino look up to him at any time in his life. Bradhsaw isn't worthy to remove Marino's Isotoner slippers.