Pitt's high-flying offense will be without its play-caller moving forward. 

Offensive coordinator Mark Whipple resigned on Tuesday morning, the school announced Tuesday afternoon. He is not expected to coach Pitt in the Peach Bowl against Michigan State on Dec. 30.

Whipple's decision — which was family-related, sources told the Post-Gazette — comes three days after Pitt's 45-21 win over Wake Forest in the ACC championship. Whipple is also a candidate to become Nebraska's new coordinator, according to a report from the Lincoln Journal Star.

"During his three seasons at Pitt, Mark Whipple was a great asset for our entire football program," head coach Pat Narduzzi said in a statement. "He did a tremendous job transitioning us from a heavy run attack to one of the best passing games in the entire country. His great work with quarterbacks was obviously on full display, given the outstanding year Kenny Pickett has enjoyed. I am very grateful for Mark's time in Pittsburgh, both personally as well as professionally, and I wish him and his family the very best moving forward."

Whipple was the head coach at the University of New Haven from 1988-93, Brown University from 1994-97 and UMass from 1998-2003 and 2014-18.

Whipple, 64, was the architect of college football's third-highest scoring offense, averaging 43 points per game in his third season with the Panthers. He was also named one of 15 semifinalists for this year's Broyles Award, given to the top assistant coach in the country.

Whipple mentored and guided Kenny Pickett during the Heisman Trophy finalist and ACC Player of the Year's remarkable 2021 season. Nationally, Pickett ranks third in passing touchdowns (42), fifth in passing yards (4,319) and third in completions of 20-plus yards (72). Pickett's Pro Football Focus quarterback grade of 92.8 sits second in the country, narrowly behind Alabama's Bryce Young (92.9).

Whipple was also a driving reason why Pickett skipped the Senior Bowl and the 2021 NFL draft and came back to Pitt, rewriting the school record books along the way.

When Pickett weighed his decision, he leaned on Whipple a great deal. The longtime NFL assistant put him in contact with former New England Patriots and Penn State coach Bill O'Brien, who offered Pickett advice. Whipple also spoke to NFL scouts and executives on Pickett's behalf to collect valuable information.

Ultimately, Pickett wanted to win an ACC championship, improve his draft stock and leave a legacy at Pitt, all of which he did. And he wanted to do it with Whipple by his side.

"If he was gone or if he wanted to retire or if he wanted to take off and play some golf — he loves to play golf. He's really good, too. Way better than me. I suck. If he left, I was definitely leaving," Pickett told the Post-Gazette in June. "He's like family now. His opinion, I mean, if he told me to leave, I would've left. He's a guy who's seen it all and done it all."

"You need confidence, and he's big on preaching that to us," Pickett said of Whipple in November. "It's not about plays. It's about players. It's about the guys who go out and do it. He puts that confidence in us. Everyone feels that."

Without Whipple, it's unclear who would call plays in Atlanta. Wide receiver coach Brennan Marion, who was hired in February, was Howard and William & Mary's offensive coordinator from 2017-19. Tight ends coach Tim Salem served as Pitt's interim play-caller in the 2015 Military Bowl.

Pitt and Michigan State kick off at 7 p.m. ET on Dec. 30 at Mercedes-Benz Stadium. The game is televised on ESPN.