Cobb threw 49 pitches over three innings before Friday night's game against Cleveland and could rejoin the Rays' injured depleted rotation late this month.
Tampa Bay manager Joe Maddon called Cobb's session impressive.
''I'm really happy with the way I came out of it health-wise and preparing to get back and face hitters,'' Cobb said.
Cobb is scheduled to throw four innings in another simulated game Monday.
Hellickson might be back in late June after arthroscopic right elbow surgery in January. Moore had left elbow ligament replacement surgery last month and could be sidelined 12-to-15 months.