"I threw 40 pitches," Rodriguez said. "I didn't feel 100 percent. I'm going to throw a simulated game on Thursday and see what happens."
While Rodriguez could not pinpoint what it was about the throwing session that left his arm feeling less than full strength, he did say there was still discomfort.
"I feel it a little bit," Rodriguez said. "I feel something. I don't know how to explain it, but I feel something."
Thursday's simulated game will provide more insight on where Rodriguez stands in his recovery. With September approaching and the end of Minor League seasons coming along with it, Rodriguez is running out of time to go on a rehab assignment. He could, however, still be eligible for potential postseason games and not subject to the Aug. 31 deadline because of his injured status.
Another injured Pirates pitcher, closer Jason Grilli, was scheduled to throw from 120 feet on Monday as well as he continues to recover from a right forearm strain.
Tim Powers is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.