The Rams are in need of a right-back with Cyrus Christie out until February at least and Paterson, whose contract expires at the end of the campaign, appears to fit the bill for McClaren.
The report states that Paterson has already made clear his intention to move to England next summer and would cost around £400,000 in compensation.
However, an earlier exit cannot be ruled out, especially if Hearts boss Robbie Neilson leaves for MK Dons, as expected.
Derby were not the only ones in attendance, though, with representatives from Sheffield Wednesday also spotted as Hearts beat Rangers 2-0 at Tynecastle, according to the Edinburgh Evening Times.
Wednesday's need for a right-back is somewhat less pressing than the Rams', however, with Jack Hunt and Liam Palmer sharing the role between them this season.
The Owls went head-to-head with Derby for Reading's Nick Blackman last January, with the striker opting for a move to Pride Park on that occasion.