From
Ken Rosenthal:
Five years will not be enough for Cliff Lee. Six might not be, either.
Lee, the prized free-agent left-hander, will receive a seven-year offer, according to major-league sources.
As of Monday night, it was not clear whether any team had extended such a proposal. But at least one club has expressed a willingness to go seven years, sources say.
...
However, one source with knowledge of the team’s thinking insisted that the Yankees do not plan to offer the pitcher a seven-year deal
Apparently, Joel Sherman's sources are saying the same thing:
I want the Yankees to sign Lee, and I also believe they fall short of #28 in 2011 without him, however, seven years might be too much. If that's what he's demanding and the Yankees decide to go in another direction, I won't blame them.