The New England Patriots will remain the preeminent Super Bowl contender so long as Bill Belichick remains the team's coach and Tom Brady remains the team's quarterback, but there's no doubt their dynasty suffered a devastating blow this offseason when tight end Rob Gronkowski decided to retire from football before his age 30 season. While there's always a chance Gronk could unretire at some point -- after all, he did just work out with Brady a few days after joking about a potential return for the playoffs -- for the time being, the Patriots will be forced to operate without the greatest tight end in the history of football. 

The Patriots have spent the offseason searching for answers at the position, but have found nothing but endless disappointment. They signed a high-upside tight end in Austin Seferian-Jenkins, but have already cut him. They lured Benjamin Watson out of retirement, but Watson has since been suspended for the first four games of the upcoming season. They tried to trade for Michael Roberts, but their agreement with the Lions fell apart due to a failed physical. We speculated that they could target an impact-now tight end in the draft, but the only two tight ends worthy of a first-round pick were long gone before the Patriots were on the clock. We thought they might trade for Kyle Rudolph, but the Vikings wound up signing him to an extension. As it stands, the Patriots' tight end group is made up of guys like Matt LaCosse, Stephen Anderson, Ryan Izzo, and Andrew Beck -- in addition to Watson, who should play a sizable role when he returns from suspension.

The Patriots can keep on searching for a Gronk replacement at tight end, but they won't ever find one. Gronk is irreplaceable. 

In his nine-year career, he averaged 68.4 receiving yards and 0.7 touchdowns per game. Consider that Tony Gonzalez, who is also in the greatest tight end ever discussion, averaged 56 receiving yards and 0.4 touchdowns per game in his career. It's not just about Gronk's contributions as a pass catcher. He was also a tremendous blocker, capable of serving as an additional offensive lineman in the run game. Even when his production slipped as a receiver as he battled injuries this past season, he was still paving the way for the run-heavy Patriots. So no, the Patriots can't replace him with one tight end. No other tight end has done what he did for the better part of a decade.

There's a scene in Moneyball where Brad Pitt, playing A's general manager Billy Beane, is talking about how the team can't replace Jason Giambi with one player. It's a little like that, minus the whole Moneyball aspect.