Young threw around 50 pitches and threw his slider for the second time. He also threw from the stretch and the windup.
Next up will either be another bullpen session or possibly a simulated game on Thursday before the Padres face the Cubs at Wrigley Field.
"I was encouraged," said Padres manager Bud Black, who watched Young's session on Monday. "He's placing some checkmarks. "He's doing fine."
Black has said he's hopeful that Young will be able to pitch sometime in September.