"We're talking about him possibly making a return this weekend," Weiss said. "We don't know what that looks like yet, but we're talking about getting him involved."
Oswalt emerged from his start with the Rookie League Grand Junction Rockies with a positive outlook and said he's still hoping to start Sunday against the Padres in place of Chad Bettis. Oswalt needed just 55 pitches to toss 5 2/3 scoreless innings in Grand Junction, allowing three hits and a walk while striking out two.
"My stuff was pretty good," Oswalt said. "All four pitches I threw for strikes and was able to spot my fastball when I wanted to. I knew they would be swinging early and I threw a lot of strikes, so a lot of one-pitch outs, two-pitch outs because I wanted to keep my pitch count down."
It was Oswalt's first time playing competitive baseball since July 7, when he pulled his left hamstring covering home plate. The primary goal for the rehab was to face live batters in a true competitive setting, Oswalt said.
Most importantly, Oswalt had no setbacks with the hamstring.
"It feels actually pretty good today," he said. "The first three innings really had no issue and got a little tired later in the game, but it didn't hurt."
Oswalt struggled in four starts with the Rockies, going 0-4 with a 7.64 ERA.
Ian McCue is an associate reporter for MLB.com.
This story was not subject to the approval of Major League Baseball or its clubs.