The New England Patriots have reached a long-term agreement with tight end Aaron Hernandez on a deal through 2018, according to sources.

The contract is expected to be signed in the next 24 hours.

Hernandez celebrated the deal by donating $50,000 to the Myra Kraft Foundation, the charity named after the late wife of Patriots owner Robert Kraft, "out of respect for Robert drafting him, [and] for doing his deal two years early."

The signing of Hernandez locks in both young tight ends that are on the Patriots roster.

All-Pro Rob Gronkowski agreed in June to a six-year, $53 million extension, the richest contract for a tight end in NFL history.

Hernandez, like Gronkowski, is entering his third NFL season. Last season he caught 79 passes for 910 yards, placing him third on the team behind Gronkowski's 1,327 and Wes Welker's 1,569 yards.

Hernandez averaged 11.5 yards per reception with seven touchdowns in 2011.

The deal is a clear indicator that head coach Bill Belichick will go through the rest of the decade with the two-tight end set as the lead concept of his offense.

Hernandez's deal casts further doubt on the long-term status of Welker. The receiver signed a $9.5 million franchise tender in May. Last month, he arrived at training camp saying it was great to be back and that he was not disappointed at not locking up a long-term deal.