Now that Jim Harbaugh has swapped NFL for college football, Alex Boone opened up about life under the former San Francisco 49ers head coach, who he described as "clinically insane".
Harbaugh left the 49ers in December to take up a seven-year, $48million deal with the University of Michigan.
The 51-year-old's departure from San Francisco was music to the ears of some players, though offensive linesman Boone was one member of the 49ers, who spoke highly of the coach last September.
However, Boone changed his tune when speaking to HBO's Real Sports in an episode to be aired on Tuesday.
"I think he just pushed guys too far," the 27-year-old said.
"He wanted too much, demanded too much, expected too much. You know, 'We gotta go out and do this. We gotta go out and do this. We gotta go out and do this.' And you'd be like, 'This guy might be clinically insane. He's crazy.'"
Boone added: "He does a great job of giving you that spark, that initial boom.
"But after a while, you just want to kick his ass. ... He just keeps pushing you, and you're like, 'Dude, we got over the mountain. Stop. Let go.' He kind of wore out his welcome."