SANTA CLARA, Calif. -- The San Francisco 49ers are making George Kittle the highest-paid tight end in NFL history. By a lot.

The Niners and Kittle agreed to a five-year, $75 million contract on Thursday, league sources confirmed to ESPN.

The deal was first reported by Barstool Sports, which reports Kittle received $40 million guaranteed for injury and $30 million guaranteed at signing.

The deal, which had been expected for most of the offseason, easily surpasses the four-year, $42 million contract Austin Hooper signed with the Cleveland Browns in March and resets the market for top tight ends.

The $40 million guaranteed is more than twice that of any other NFL tight end, and the $30 million guaranteed at signing also is a record amount -- $12 million more than Hooper received.

The Niners and Kittle went through a lengthy contract negotiation, which began after the Super Bowl and was complicated by the coronavirus pandemic. The potential for a revenue shortfall from playing games with no fans in the stands -- and an ensuing salary-cap drop -- created uncertainty about how to structure a potential deal.

Kittle reported to training camp and participated in all team activities without so much as a threat of a holdout. Because the sides remained amicable throughout the process, general manager John Lynch and coach Kyle Shanahan remained optimistic that a deal would get done as the Niners opened camp.

"I think we don't have to say how important George is to us and not only as being the best tight end to me in the league, but also the type of person he is," Shanahan said on Aug. 3. "So, we're doing everything we can to get that done. ... I feel really good about this going forward and I feel very optimistic about it. Hopefully something will happen sooner than later. I'm not too concerned about it, though."

This summer, NFL players ranked Kittle as the seventh-best player in the league, regardless of position. He has racked up 2,945 receiving yards -- the most by any tight end in NFL history after three seasons, surpassing Mike Ditka and Rob Gronkowski. In 2018, Kittle set the record for most receiving yards in a season by a tight end when he finished with 1,377. Over the past two seasons, Kittle ranks sixth in the NFL among all pass-catchers with 2,430 receiving yards, is 11th with 173 receptions and is second with 1,464 yards after the catch.

Beyond his receiving prowess, Kittle is also widely regarded as one of the best blocking tight ends in the league. In two games without him in 2019, the 49ers averaged 2.63 yards per carry and 60.5 rushing yards with no touchdowns on the ground. In the 14 games he played, the Niners averaged 4.83 yards per carry and 156 rushing yards per game with 23 rushing touchdowns.

All of that earned Kittle a Pro Bowl nod in each of the past two seasons, a second-team All-Pro spot in 2018 and a first-team All-Pro spot in 2019.