Reuters

If Patriots tight end Rob Gronkowski commemorates a Super Bowl loss by dancing with his shirt off, we suggest averting your eyes for his post-mega-contract victory celebration.

Per a league source, Gronkowski has signed a six-year contract extension. The deal carries, we’re told, $54 million in new money.

Given that he already was under contract for two more years, the deal binds Gronkowski to the team for eight seasons, putting him under contract through 2019.

The contract includes an $8 million signing bonus, a fully-guaranteed 2012 base salary of $540,000, a fully-guaranteed 2013 base salary of $630,000, and a fully-guaranteed base salary of $3.75 million in 2014.

He also has workout bonuses of $30,000 in 2012 and 2013, and a guaranteed workout bonus of $250,000 in 2014.

His $4.75 million base salary and $250,000 workout bonus for 2015 are guaranteed for injury prior to end of 2014 league year, then guaranteed fully.

The guarantee on signing is $13.17 million, and another $5 million is guaranteed for injury. The total cash for the next four years will be $18.23 million, which exceeds the combination of Gronkowski’s prior contract for the next two years and two years of the franchise tag.

The Pats face a decision in 2016, at which time a $10 million option bonus comes due. If the Patriots pick up the option (factors will include whether Tom Brady is still the quarterback, and whether Bill Belichick is still the head coach, and whether Gronkowski is still playing at a high level), the final four years include salaries of $8 million in 2018 and $9 million in 2019.

The new money over six years averages $9 million annually. Factoring in the existing two years, the deal is worth less than $7 million per year — assuming that the Patriots pick up the 2016 option and honor the full eight years of the deal.

For now, it’s definitely a three-year, $13.23 million deal, and $18.23 million over four if he’s not cut after three seasons.

Given that Gronkowski has only two years in the league and would make only a little more than $1 million over the next two seasons, then face the franchise tag up to twice, a very strong case can be made for taking the money now, especially since the Patriots rarely open the vault early, if ever. After missing a full season in college with a spine injury that required surgery, more than $13 million guaranteed now is a lot more than the $1 million in change he would have made while carrying the full injury risk for two full seasons.

The Patriots now have the ability to use the franchise tag on tight end Aaron Hernandez in 2014, if they can’t get a long-term deal done with him.