Baker, who is upset with the Jets over his contract, rode the stationary bike during the session.
Mangini was asked by a reporter why Baker was held out of practice.
"He wasn't held out of practice," Mangini said.
So it stands to reason that Baker, who had back problems last year, asked out of practice with the "back" problem.
And after practice, Baker blasted the team's management over his current contract, and said he would like Eric Mangini to get involved in the situation.
Baker is in the third year of a four-year contract that averages $1.65 million. The Jets new right tackle Damien Woody, coming off a disappointing stint in Detroit, signed a deal that averages $5 million a year with the Jets this off-season. Outside linebacker Bryan Thomas, coming off a poor season, is also making an average of $5 million per season.