Cobb, 28, caught 38 passes for 383 yards and two touchdowns in 2018 for the Green Bay Packers.
It was a down year for Cobb, who only appeared in nine games because of a hamstring injury.
In his prime, he had three seasons with at least 75 receptions, 800 receiving yards and six touchdowns, though he could never quite replicate his 2014 campaign (91 receptions, 1,287 yards, 12 touchdowns).
Still, he is effective out of the slot, a position of need for the Cowboys after Cole Beasley signed with the Buffalo Bills.
Todd Archer @toddarcher
The Cowboys are hosting free-agent wide receiver Randall Cobb at The Star today, according to a source. With the departure of Cole Beasley, the Cowboys are looking for help at slot receiver and Cobb can also play on the outside. In eight years in Green Bay, he had 470 catches...
The Cowboys also declined Terrance Williams' option this offseason.
Amari Cooper is locked in as the team's No. 1, while Michael Gallup and Allen Hurns are options on the outside, but Beasley was a playmaker out of the slot.
With many of the top slot options already signed, like Adam Humphries and Jamison Crowder, Cobb is arguably the top player remaining for that role.