"Robinson is focused on preparing for and playing the 2013 season,'' Boras told CBS Sports' Jon Heyman. "By agreement, discussions shall remain confidential. Also by agreement, discussions will cease if they are a distraction to Robinson's performance and leadership of the 2013 Yankees.''
Earlier this month, managing general partner Hal Steinbrenner had said the team was "willing to consider a significant long-term contract" to keep Cano in pinstripes, but Steinbrenner did not publicly acknowledge an actual offer had been made.
"I thought Hal announced that we made a significant offer, and we've had a few conversations," Cashman said. "I thought I was restating Hal's stuff. If I said a little more, that's all I'm saying."
Cashman would not say when the offer was made, or if it has been rejected by Cano and Boras.
Cano, 30, is entering his final season under contract with the Yankees after his $15 million club option was picked up in October. A two-time American League Gold Glove Award winner and four-time AL Silver Slugger Award winner, Cano batted .313 with a career-high 33 homers and 94 RBIs last year.
The move represents a departure from the normal stance of the Yankees, who have waited for contracts to expire before opening negotiations on a new deal, as they have done with shortstop Derek Jeter and closer Mariano Rivera in recent years.
"Usually it's applying to older guys -- [age] 37, 38, 39," Cashman said. "We have a policy. Since we're the team, we have the right to change our minds -- especially ownership."
Boras typically prefers to bring his clients to the free-agent market, and it has been speculated that Cano could seek a contract of eight to 10 years at $20 million to $25 million per season if he reaches free agency.
Cano has said numerous times that he does not want to discuss his next contract at this point of the year.
"It's not about the money, but like I've said, I don't want to go into details right now," Cano said recently. "I'm just focused on playing the game and just helping the team win another championship."
Cashman pointed out that the Yankees have made extension offers before deals expire in the past; New York reportedly offered catcher Russell Martin a three-year, $20 million deal last March, which was rejected.
"It's not like it's a country club, and here's the code of conduct that you can't deviate from," Cashman said. "We've had a history of doing things a certain way, but that doesn't mean you have to do it that way every day.
"Whatever conversations and however you want to define them with Robbie, it isn't something new or different, because we did it with Russell last March."