Sam Demel threw for Triple-A Reno on Thursday, recorded an inning of work and induced three ground-ball outs. He threw 12 pitches, seven for strikes and five for balls.
Juan Gutierrez threw a simulated game on Thursday and is scheduled to throw another simulated game on Sunday. Injured infielder Geoff Blum is expected to hit off him.
"He had a lot of life on his fastball," D-backs manager Kirk Gibson said. "Down in the zone, impressive life and excellent body language."
Gibson said Blum will start playing in the rookie level Arizona league next week. He has been limited to simulated games to this point.