The Ryan brothers will reunite on the sidelines for the first time in two decades, as Rob Ryan has agreed to join head coach Rex Ryan's defensive staff with the Buffalo Bills.

Rex Ryan released a statement on the news Sunday evening and appeared on ESPN Radio on Monday morning:

On Tuesday, Alex Marvez of Fox Sports reported defensive coordinator Dennis Thurman is "expected to work more with [defensive backs] now while Rex/Rob run the defense."

The New Orleans Saints fired Rob Ryan in November after he served as the team's defensive coordinator for two-plus seasons. Under Ryan, the Saints defense sank to the bottom of the league in 2015, giving up the most points per game on the season (29.8).

Rex Ryan, hired as Buffalo's head coach in 2015 after six seasons as the head coach of the AFC East rival New York Jets, has eight defensive coaches on his staff.

Rob Ryan has been a full-time defensive coordinator every year since 2004 and jumped from the Oakland Raiders to the Cleveland Browns to the Dallas Cowboys before landing in New Orleans.

Rob and Rex Ryan last coached together from 1994 to 1995 under their father, Buddy Ryan, with the Arizona Cardinals, where Rob oversaw defensive backs and Rex coached the defensive line and linebackers.

Rex Ryan's Bills finished 8-8 on the season, and although they missed the playoffs, they prevented the Jets from making it with a 22-17 win in Week 17. Still, Rex hasn't reached the postseason since the 2010 season.