How Pats would deal with losing Gronk

Rob Gronkowski will likely require a fourth surgery on his left forearm, according to sources, which would mean 10 additional weeks of recovery and would put his availability for the start of the 2013 season in question.

* Why surgery would hurt the Patriots: This would be a significant blow for a Patriots team that already lost leading receiver Wes Welker, who signed with the Denver Broncos this offseason.

No team relies on its tight ends more than the Patriots. Since 2010, when the Patriots drafted Gronkowski and Aaron Hernandez, New England has the highest percentage in the NFL of receiving production coming from tight ends.

When Gronkowski is healthy, he has proven to be one of the most productive receivers in the league.

His 38 career touchdowns are the third-most by any player in his first three seasons in NFL history. Only Randy Moss (43) and Jerry Rice (40) had more. Grownkowski is also the first tight end in NFL history to have at least 10 touchdown receptions in each of his first three NFL seasons.

Gronkowski has been Brady’s favorite target in the end zone over the last two seasons.

Brady has completed more than two-thirds of his throws to Gronkowski since 2011 and less than a quarter of his passes to all other Patriots.

Gronkoski’s 20 touchdowns on throws to the end zone since 2011 are by far the most of any player in the league.

Gronk was also one of the most valuable members of the Patriots offense last year. When Gronkowski was on the field during the regular season, the Patriots averaged more yards per play (6.1 vs. 5.4) and Brady had a better completion percentage (66 percent vs. 58 percent) compared to when he was off the field.

* Why the Patriots can survive without Gronk: The Patriots have prepared for life without Gronkowski, after he missed five regular season games last year along with the playoff loss to the Baltimore Ravens.

Even though Gronkowski could miss some time, it doesn’t mean the Patriots' two-tight-end offense will go away. In Weeks 11-15 last year without Gronkowski, the Patriots used multiple tight end sets on 55 percent of their plays, which was actually higher than the 45 percent rate in Weeks 1-10 with Gronkowski.

New England also signed wide receiver Danny Amendola in the offseason to replace Welker. Amendola has the skills to fill the slot receiver role that Welker perfected in the Patriots' passing game.

His average target distance over the last four seasons is the shortest in the league and he nearly matched Welker's per-game production when lined up in the slot last season.

Amendola is also more sure-handed than Welker, who’s 11 drops last season were the second-most in the NFL. Since 2010, Welker has caught passes at a rate of 12.5 receptions for every drop. Amendola’s success rate is better at 21.9 receptions per drop.