Pitching on a warm 83-degree afternoon (at first pitch), Guzman allowed one hit (a single) and a walk in three innings. He threw 34 pitches, 20 strikes.
Most of his work was courtesy of the fastball – typically 87-88 mph for most of the day, with the right-hander topping out at 90 mph. That was a bit of a drop from his Aug. 12 outing at Class AA Tennessee. In that start, Guzman was topping out in the mid-90s.
He said he couldn't explain why his velocity was down Sunday.
"I've been throwing in the middle 90s," Guzman said after the game. "I don't know what happened. It (arm) feels great, but it's just one of those things."
Did the heat have anything to do with it? It was the hottest conditions Guzman had pitched in since beginning his rehab earlier this month at Class-A Daytona.
"Maybe, I don't know," Guzman said. "I felt good. … You don't want to go full strength in the first inning, so I was trying to save strength for the last two."
Guzman began the game by striking out Zephyrs leadoff hitter Jesus Feliciano on three straight fastballs. The hardest hit ball against him came later in the first inning when Chris Aguila lined out to deep center field.
Away from his fastball, Guzman threw only two curveballs and three changeups.
"He looked good. His velocity was good, he threw strikes, (and) he worked ahead. He only threw 34 pitches and had a really good outing," said Iowa manager Pat Listach.
"He's on the way back. He's going to pitch again here in a few more days."
Now 11 months after his surgery, Guzman says he's continuing to take things day by day. He said he would like to join the Chicago roster prior to September 1 (thus being eligible to make a post-season roster), but that it was not entirely in his hands.
"Whatever they'd ask me to do, I'd do," said Guzman. "I just have to stay ready and be there for everything."