"For him, I'm sure a year-and-a-half at the same level, he's champing at the bit to get to that Triple-A level," Reds manager Bryan Price said.
Listed by MLBPipeline.com as the Reds' No. 1 prospect and No. 18 in the Top 100, Stephenson was 4-7 with a 3.68 ERA in 14 starts for Double-A Pensacola. Over 78 1/3 innings, he walked 43 and struck out 89 while averaging 10.2 strikeouts per-nine-innings.
Reds general manager Walt Jocketty watched Stephenson pitch a few times, including earlier this season.
"He's been much more consistent," Jocketty said. "He got in trouble, I've seen several times, early and then settled in and was unhittable the rest of the game. He finally got over that hump where he was able to get off to a better start initially in the game. That was one thing we were trying to get him past. He's been very successful at that the past several starts."
Stephenson, the Reds' first-round pick in the 2011 Draft, had a 2.53 ERA in his five June starts after a slow start to this season.
With the possibility of the Reds being sellers before the July 31 non-waiver Trade Deadline, there could be rotation vacancies if starters Johnny Cueto and Mike Leake are dealt. That could open a spot for Stephenson, potentially.
"We'll see how he does," Jocketty said. "I'm anxious to see how he does at Triple-A. Hopefully, we can put him on a faster track where he could certainly be in the mix for next year, if not later this year."
Price liked the reports of how Stephenson has developed his secondary pitches to go with a fastball that can reach the high 90's mph.
"We're excited he's throwing the ball consistently, getting his curveball over, which was something he was challenged to do earlier in the year and he's had kind of a split-changeup that he's incorporated into his mix," Price said. "It gives him a real quality third pitch."
• Lefty reliever Tony Cingrani, who has been on the disabled list since June 15 with a left shoulder strain, worked two scoreless innings with one walk and three strikeouts in his rehab assignment appearance for Louisville on Friday. Cingrani, who threw 35 pitches, began the completion of a suspended game for Louisville vs. Columbus before Stephenson was to take the mound in the regularly scheduled game.