Bill O’Brien’s two-year run as Alabama’s offensive coordinator has come to an end.

The New England Patriots hired O’Brien as their offensive coordinator Tuesday, ESPN reported. It will be O’Brien’s second stint calling plays for the Patriots after the Massachusetts native previously led New England’s offense from 2009-11.

The two-year contract O’Brien signed with Alabama in 2021 was set to expire at the end of February, and his return to the NFL was long speculated.

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O’Brien is the third of Nick Saban’s assistant coaches to depart this offseason. Defensive coordinator Pete Golding left for the same position at Ole Miss, while safeties coach Charles Kelly took Deion Sanders’ defensive coordinator job at Colorado.

The departures of both coordinators shakes up what had been a period of relative stability on Saban’s staff, with Golding serving four seasons in his role and O’Brien the past two seasons following two seasons of Steve Sarkisian as offensive coordinator.

Alabama’s offense had averaged at least 47 points per game and 500 yards per game in Sarkisian’s tenure but the production slipped slightly under O’Brien. After averaging 488 yards and 39.9 points per game in 2021, the Tide gained 488 yards per game and 41.1 points per game this season. Those averages ranked 11th and fourth among FBS teams, respectively.

But Alabama lost four games over the past two seasons, all to SEC rivals, and narrowly won other contests while falling short of a national championship. That increased the heat fans put both on O’Brien and Golding, with Saban defending the work of both coordinators during a November interview with ESPN.

“It’s my responsibility,” Saban said. “I know what plays they call; I’m involved in how they prepare for the week. I watch practice film with them. But I think people look for somebody to hate when things don’t go right. But most of the stuff comes down to a lack of execution. It’s not really what you’re doing, it’s how did you do it?”

Saban gave O’Brien a public vote of confidence during the 2021 season, saying, “I actually think he’s done a pretty good job.” But when asked about O’Brien’s job performance last November, Saban responded during a news conference, “I’m not gonna analyze somebody publicly, good, bad or indifferent.”

O’Brien began his coaching career as an assistant for multiple ACC schools but is most known for his work coaching then-Patriots quarterback Tom Brady and later serving as head coach for Penn State (2012-13) and the Houston Texans (2014-20).

When the Patriots lost offensive coordinator Josh McDaniels to the Las Vegas Raiders in early 2022, O’Brien was speculated as a candidate to replace him. But O’Brien remained at Alabama, later speaking about his two-year commitment he made to Saban, and the Patriots instead turned to offensive line coach Matt Patricia, a longtime defensive coach, to call their offensive plays in 2022.

The result was a significant drop-off in production for the Patriots’ Mac Jones-led offense, which prompted the Patriots to announce earlier this month they would fill the offensive coordinator job. O’Brien was one of five reported candidates to interview but was long considered the favorite.

Alabama will look to fill its offensive coordinator position while it also begins the process of replacing two-year starter Bryce Young at quarterback. The rest of its offensive staff — running backs coach Robert Gillespie, wide receivers coach Holmon Wiggins, tight ends coach Joe Cox and offensive line coach Eric Wolford — has thus far remained intact.

Mike Rodak is an Alabama beat reporter for Alabama Media Group. Follow him on Twitter @mikerodak.