By Shalise Manza Young, Globe Staff

The Patriots have locked up tight end Rob Gronkowski for a long time, agreeing to a deal that amounts to eight years with a maximum value of $55.1 million, a league source tells colleague Greg A. Bedard.

That means Gronkowski is signed through the 2019 season -- in theory.

News came this morning that the two sides were working on an extension, and while a source said there was nothing final yet, clearly the deal was close to being done.

Gronkowski still has two years remaining on the four-year contract he signed as a rookie in 2010, and NFL Network's Albert Breer reports that while the tight end won't receive a bump in base salary for 2012 and '13, he will get new money in the form of an $8 million signing bonus now.

We say it's through 2019 in theory because ProFootballTalk reports that in 2016 there's a $10 million option bonus, and the Patriots will have to decide whether or not to pick that up. If they do, Gronkowski's salary in 2018 will be $8 million and in 2019 it will be $9 million.

It looks like the deal is for three years, $13.23 million at a minimum -- about what Brandon Lloyd got from New England -- and if Gronkowski isn't cut after three years, it's $18.23 million over four years.

We'll post more details as they come in.