Duke, who has been on the disabled list since June 23 with a left elbow flexor pronator strain, said he felt no discomfort in his elbow during the session, which was his first from the mound since the injury.
Russell also remained optimistic that second baseman Neil Walker could play Saturday, though he said that's a decision he cannot make before seeing how Walker responds to Friday's infield work and batting practice. He has not played since suffering a concussion June 25 after colliding with Ryan Church during a fly-ball play in Oakland.
Rookie left fielder Jose Tabata, meanwhile, said his left hand still hurts when he squeezes the bat while swinging, but he still led off Friday for the Pirates.
Tabata suffered the injury when he was caught stealing in the fourth inning Thursday, as Phillies shortstop Jimmy Rollins accidentally stepped on Tabata's left hand while making the tag on the outside part of second base.