The two-time Pro Bowl guard, upset with negotiations over a new contract, skipped the start of the team's three-day minicamp on Tuesday after saying he wants to be traded.
Mankins was not required to attend since he's unsigned after completing his original five-year contract. He's a restricted free so any team that makes an offer would have to part with a first- and third-round draft choice if the Patriots don't match it.
"At this point, I'm pretty frustrated, from everything that's happened and the way negotiations have gone," Mankins told ESPN Boston on Monday. "I want to be traded. I don't need to be here any more."
Coach Bill Belichick wouldn't address the issue when asked about it four times during his news conference before Tuesday's practice.
"I think the situation between anybody and the club, the contract situation, is between them and the club," he said. "I'm focusing on coaching the players that are here."
Asked if Mankins had told him or the club directly that he wants to be traded, Belichick said, "I think we already talked about that."
Because the NFL is in a season without a salary cap, players with four or five years experience who could have become free agents during a capped year now must wait until they complete their sixth season.
The Patriots made a $3.268 million, one-year tender offer to Mankins, the 23rd overall draft pick in 2005. When he didn't sign it by the deadline of 11:59 p.m. Monday, the team exercised its right to lower it to $1.54 million, according to the Boston Globe.
The Globe reported that the Patriots also offered a five-year contract at about $7 million per year. The Boston Herald reported that the deal was worth more than $7 million per year.
Mankins' agent, Frank Bauer, did not return a phone call seeking comment Tuesday.
Patriots who did attend the minicamp had little to say about the absent player.
"We understand his situation but we're all out here working and getting better," linebacker Tully Banta-Cain said. "I'm pretty sure they'll get that resolved when the time is right."
Nose tackle Vince Wilfork was upset a year ago when he had one season left on his contract but wanted an extension. Unlike Mankins, he was still under contract and reported to the mandatory minicamp in 2009. After the season, Wilfork signed a five-year, $40 million contract.
He declined comment on Mankins' situation.
"I'm not going to touch that because I have nothing to do with Logan's situation, so I'll leave that up to Logan to talk about," Wilfork said. "I'm pretty sure everybody that's out here now is just excited to be back because, being away from the game for a couple of months, everybody kind of misses it."
Barring a change of heart, Mankins won't be back with the Patriots at all.
After the 2008 season, he and his agent asked the Patriots about an extension but were told that owner Robert Kraft wanted to wait because of the uncertain NFL labor situation, ESPN Boston reported.
"I was asked to play '09 out, and that they would address the contract during the uncapped year. I'm a team player, I took them at their word, and I felt I played out an undervalued contract," Mankins told ESPN Boston.
"Right now, this is about principle with me and keeping your word and how you treat people. This is what I thought the foundation of the Patriots was built on. Apparently, I was wrong. Growing up, I was taught a man's word is his bond. Obviously this isn't the case with the Patriots."