That doesn't mean that Gonzalez, who turns 28 in September, won't one day become a starting pitcher.
"Right now he is doing what he needs to do," said Joe Jordan, the Phillies' director of player development. "Long-term, he can end up in the rotation."
The Phillies' original investment in Gonzalez was expected to be at least $48 million, but the team doctors didn't like what they saw on his medical report. Eventually, the $12 million deal was negotiated.
Gonzalez was shut down after just two spring training appearances with right-shoulder tendinitis. He made his debut with the Clearwater Threshers on May 15. After three starts totaling just 91/3 innings, he had a 6.75 ERA. He then was sidelined with a "dead arm." When Gonzalez returned to the Threshers on June 20, he was pitching out of the bullpen.
Gonzalez made his first appearance for Reading on July 2.
"I feel good pitching as a reliever," Gonzalez said through an interpreter. "As for the future, it is not up to me, and I can do anything the Phillies want me to do."
He has regained the fastball that led the Phillies to sign him. Gonzalez was recently clocked at 97 m.p.h.
"Earlier this year I was feeling frustrated, but now the injury is gone and I am back to where I was, and I am healthy and looking forward to pitching," Gonzalez said.
The 6-foot-3, 200-pound Gonzalez had not pitched much the previous two years. He tried to defect from Cuba in early 2012 and failed, and was subsequently barred from pitching competitively.
After a successful defection to El Salvador in 2013, he took up residency in Mexico, where he pitched briefly before the Phillies signed him.
"He has done very well and looks as strong and healthy as he has looked since I first saw him in spring training," Jordan said. "He is pitching with a lot of confidence and likes to compete, something we have been able to see at Clearwater and Reading."
Reading manager Dusty Wathan believes Gonzalez could be successful as a starter or a reliever.
"He is pitching like a starter out of the bullpen because he has four quality pitches," Wathan said. "He is using all his pitches."
The four pitches are a fastball, change-up, slider, and curve.
"He has thrown them all for strikes," Wathan said.
He could be throwing for the Phillies by the end of the season.
"I have a lot of hopes for the big leagues," Gonzalez said. "I came here to keep working, and I think I can get [to the Phillies] sometime this season."