FOXBOROUGH, Mass. — Josh McDaniels is returning to the New England Patriots to take over as offensive coordinator next season for Bill O’Brien, who was introduced Saturday as Penn State’s new coach.

A person familiar with the situation told The Associated Press that McDaniels is expected to serve as an offensive assistant under O’Brien for the rest of this season. The person spoke on condition of anonymity because the team hasn’t made an announcement.

The move was first reported by ESPN.com.

O’Brien said at his news conference Saturday he intends to remain the Patriots’ offensive coordinator as long as they stay in the playoffs.

McDaniels would go from near the bottom of the NFL after spending the season as offensive coordinator of the St. Louis Rams, who were 2-14, to a shot at the Super Bowl with the Patriots with an AFC-best 13-3 record.

He was offensive coordinator with the Patriots from 2006 to 2008 before becoming head coach of the Denver Broncos in 2009. He was fired with a 3-9 record in 2010 after losing 17 of his last 22 games. The Patriots, who had a bye this weekend, go into the playoffs with an eight-game winning streak.

The 35-year-old McDaniels was the only Rams assistant under contract through next season when Steve Spagnuolo was fired on Jan. 2.

“I’m sure Josh will have opportunities around the NFL to possibly be a coordinator or better throughout this process,” Kevin Demoff, the Rams vice president and chief operating officer, said at the time. “It’s going to be fluid, but we’ll figure out what’s best for both parties.”

The Rams scored the fewest points per game in the league, 12.1, gained the second fewest yards, 283.6, and the third fewest yards passing, 179.4. Sam Bradford struggled at quarterback with just six touchdown passes and six interceptions in McDaniels’ system, which had many more longer developing pass plays than the Rams had in 2010 under Pat Shurmur.

That lack of production contrasts sharply with the Patriots offense under McDaniels, especially in 2007 when they went 16-0 then won two playoff games before losing the Super Bowl to the New York Giants 17-14.

In that season, Tom Brady set a single-season league record with 50 touchdown passes for an offense that averaged a league-best 411.2 yards. It also was first in yards passing, 295.7 and points per game, 36.8.

Now McDaniels is poised to be reunited with Brady and another prolific offense in time for the Patriots practices for their divisional playoff game next Saturday. As the top-seeded team in the AFC, they earned home-field advantage throughout the conference playoffs.

The Patriots were second in the league in overall yards with 428 per game and yards passing with 317.8. Their average of 32.1 points was third.