The right-hander, who underwent Tommy John surgery one year ago, picked up a win in relief Friday for Triple-A Iowa, whose magic number to clinch the Pacific Coast League North Division was down to one. The Iowa Cubs rallied to beat Oklahoma, 12-10, on Friday.
Guzman, whose 30-day rehab assignment will end on Sept. 1, will be one of the players called up when Major League rosters expand. Cubs player development director Oneri Fleita said the young pitcher's velocity has been good in his five games so far.
In two outings at Iowa, Guzman has given up four hits and struck out five over five innings. He has worked his way up through the Minor League system in his rehab, beginning at Class A Daytona.
Fleita said he also was encouraged by outfielder Felix Pie, who was batting .284 at Iowa with nine homers and 47 RBIs.
"It looks like he's more patient," Fleita said. "The numbers are more consistent."
The big league team has yet to determine who will be called up on Sept. 1, and Fleita said they may tweak the Iowa roster and add some players from Double-A Tennessee to help the team in the PCL playoffs.
"We want to give them a chance to win," Fleita said.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.