Former Tennessee Titans tight end Jonnu Smith reached agreement with the New England Patriots on a four-year, $50 million deal that includes $31.25 million fully guaranteed, agent Drew Rosenhaus told ESPN's Adam Schefter.

The $12.5 million average annual value in Smith's deal is the second most the Patriots have given to a free agent in the last 10 years behind cornerback Stephon Gilmore's deal in 2017, which averages $13 million per season, according to ESPN Stats & Information.

The Patriots entered Monday among the NFL's leaders in salary-cap space, and they were motivated to address tight end, as life after Rob Gronkowski has been a challenge for them. Over the last two seasons, they have the fewest receptions (55), receiving yards (673), targets (87) and receiving touchdowns (3) from tight ends in the NFL.

Smith took advantage of being the Titans' primary tight end last season by scoring a career-best eight touchdowns, second most on the team. He also had 41 receptions for 448 yards.

All eight of Smith's touchdowns came in the red zone. The Patriots as a team had seven touchdown receptions in the red zone last season, fewest in the NFL, according to ESPN Stats & Information data.

Smith, 25, got off to a hot start and scored five touchdowns over the first four games, but he was slowed by an ankle injury in October.

An injury to left tackle Taylor Lewan then caused the Titans to use Smith's blocking ability to help Lewan's backups. While Smith's production dipped as a result of being asked to chip defensive ends, his versatility became more evident.

The tight end was selected in the third round of the 2017 draft. In four seasons, he has caught 114 passes for 1,302 yards and 16 touchdowns. Smith was also used in the backfield at times and carried the ball six times for 82 yards, including a 57-yard touchdown run against the Houston Texans in 2019.

ESPN's Mike Reiss and Turron Davenport contributed to this report.