INDIANAPOLIS -- Dan Marino is both proud and a bit surprised that his single-season passing yardage record has stood the formidable tests of time and rules changes.
He doesn't expect it to last much longer.
The former Miami Dolphins QB set the record of 5,084 yards in 1984, but if the league's quarterbacks continue at their current pace this season, New England's Tom Brady, New Orleans' Drew Brees, Green Bay's Aaron Rodgers, Dallas' Tony Romo and Carolina rookie Cam Newton all would surpass his total, and San Diego's Philip Rivers and Detroit's Matthew Stafford would be knocking on the door.
One QB having a great season would be understandable. But after 27 years, why the sudden outburst?
Marino, now a CBS Sports studio analyst, says the game has changed. The rules limit contact by defensive players and severely penalize many of the bone-jarring hits that made the safeties and linebackers of his era famous. Tight ends and running backs are more versatile, the no-huddle offense is more common, teams throw more than ever and receivers are bigger, stronger and faster.
With all those factors, Marino concedes that it's probably just a matter of time before one of the league's longest-standing major offensive records falls.
"I don't want anybody to break it," the Hall-of-Fame quarterback said, laughing. "There's a lot of guys that are going to have a chance to break it, I'm sure."
Brady appears to have the best chance. Through five games, he has passed for 1,874 yards -- a pace for nearly 6,000 yards.
That success is in large part due to his connection with Wes Welker, who has a league-high 740 yards receiving and is on pace to gain 2,368 yards. That would shatter Jerry Rice's record of 1,848 yards set in 1995.
Marino likens the Brady-Welker combination to the connections he had with Mark Clayton and Mark Duper.
"They're very instinctive," Marino said. "They've been together for a while now. They understand coverages. Wes Welker probably understands what Tom Brady is thinking at the line of scrimmage."
It's not just the top players who are producing eye-popping numbers. Through five weeks, minus Monday night's Chicago-Detroit game, the NFL is producing 489.7 combined yards passing per game. That's well ahead of the full season record of 443.1 set just last season.
"I've never seen anything like it," Marino said. "I think it's amazing."
Teams are also completing passes at a near-record rate of almost 61 percent.
The most shocking aspect of this year's increase is that it doesn't appear to be attached to a specific rule change.
The league saw an immediate spike in passing stats after the 1978 rule change outlawing contact beyond five yards downfield. There were additional spikes in 1996 and 2004 after the NFL pledged stricter enforcement of the rule.
Quaterbacks have passed for 4,500-yards in a year 22 times in NFL history. Fourteen of those great seasons have come since the start of the 2004 season.
"I think over the last four or five years or whatever it is, people are figuring out how to take advantage of the rules," San Diego coach Norv Turner said. "It's a big deal. I tell our guys, the rules have been set up for offensive football and for scoring. The big thing defensively I think now is you have to get stops. You have to find a way to get turnovers and get stops, because teams are going to get yards, particularly teams with quarterbacks of that caliber that have put that time into the passing game."
The most recent changes to affect the passing game are the 2009 rule that protects quarterbacks from being tackled below the knees and bans on blows to the head, strictly enforced last year, that were designed to limit injuries to defenseless receivers.
The sheer number of passing attempts give today's quarterbacks a chance at Marino's record, too. Marino threw 564 passes in his record season; when Brees came within 15 yards of the record in 2009, he threw 635 times.
Teams on average have combined to throw an all-time high of 70 times a game this season -- meaning 70 passing attempts between the two clubs playing. In 1984, they threw a combined 64 passes per game.