SANTA CLARA >> George Kittle’s days as the most prolific tight end in 49ers history are now numbered … through at least 2029.

Kittle has signed a four-year extension on his contract, which was set to expire after the 2025 season.

The $76.4 million deal averages $19.1 million per year and makes Kittle the NFL’s highest-paid tight end, as first reported by Bussin’ With The Boys, a podcast featuring former NFL players Will Compton and Taylor Lewan. Kittle gets $40 million guaranteed, including $35 million at signing and $5 million in 2027.

Kittle was slated to make a $14.4 million base salary this season and count $22 million against the salary cap, the latter of which ranks highest among NFL tight ends. However, the Arizona Cardinals’ Trey McBride reset their market April 3 when he agreed to a four-year contract worth $19 million per season, vaulting him ahead of Kittle, Kansas City’s Travis Kelce ($17 million per year) and Minnesota’s T.J. Hockenson ($16.5 million).

“In 2017, our first year with the 49ers, we selected a skinny tight end from Iowa whom we were really excited about. We had high hopes, but no one knew that he would become the player that he is today,” general manager John Lynch said in a statement. “George’s leadership, enthusiasm for the game, for his teammates, and the Faithful are truly unique and special.”

Kittle, the seven-time captain, six-time Pro Bowler and five-time AP All-Pro, showed up Friday to work out as the 49ers concluded the first week of their voluntary offseason program.

Kittle’s deal comes as the 49ers are negotiating an extension with Brock Purdy before he enters the fourth and final year of his rookie contract.