Pouncey is in Boston, a National Football League source told the newspaper Thursday.
Sports Illustrated reported Pouncey was formally subpoenaed by a Massachusetts grand jury to question him on what he knows about Hernandez, his former college roommate at the University of Florida.
Hernandez, a former player with the New England Patriots, has been charged with the murder of Odin Lloyd.
Prosecutors have broadened the scope of the investigation to include Hernandez' possible involvement in interstate gun trafficking. It is unclear if Pouncey is viewed by authorities as a witness or as a possible suspect, the Miami Herald said.
Pouncey is expected to play for the Dolphins in their home game Sunday against the Patriots.