"He would have been a high Draft pick," Reds senior director of amateur scouting Chris Buckley said. "He's already well into his rehab. We're taking a little risk but he wants to come out."
In 2013, Lopez had a 3-3 record and 3.40 ERA in 20 games, including five starts. He had 42 strikeouts and 18 walks over 47 2/3 innings while opponents batted a team-best .180 against him.
"He was 94-97 [mph] with a hard slider," Buckley said. "He got hurt at the end of the fall and tried to rehab it and then had the surgery."
This isn't the first time that the Reds have landed a pitcher from Seton Hall. Reliever Nick Christiani, who was a 13th-round pick in 2009, made his big league debut last season and was on the Opening Day roster this season.
The Draft concludes Saturday, with exclusive coverage of Rounds 11-40 beginning on MLB.com at 1 p.m. ET.