Butler's presence is an indication that he is fully committed to the Patriots for 2017 despite the sides not reaching a long-term contract extension, and the Patriots signing free-agent cornerback Stephon Gilmore to a top-of-the-market five-year, $65 million contract.
Butler was a restricted free agent this offseason and drew interest from the New Orleans Saints, who hosted him on a visit. But the Saints elected not to sign Butler to an offer sheet, in which they would have had to surrender a first-round draft choice (No. 11 overall) had New England not matched it.
After Butler signed his $3.91 million tender, New England and New Orleans discussed a trade, but they ultimately didn't strike a deal. The Saints drafted Ohio State cornerback Marshon Lattimore with their No. 11 overall pick.
Butler is scheduled for unrestricted free agency after the 2017 season. His presence at voluntary offseason workouts comes in the week that the Patriots have entered the second phase of work, which includes coaches being allowed to work with players on the field for the first time.
Butler is projected to start alongside Gilmore, giving the Patriots one of the NFL's best 1-2 cornerback duos. Butler played 96.7 percent of the defensive snaps in 2016, and had played 98.8 percent of the defensive snaps in 2015 when he was voted to the Pro Bowl.