MLBPipeline.com named Stephenson the No. 24 prospect, while Winker was two spots behind at No. 26.
The annual ranking of baseball's Top 100 Prospects is assembled by MLBPipeline.com Draft and prospect experts Jonathan Mayo and Jim Callis, who compile input from industry sources, including scouts and scouting directors. It is based on analysis of players' skill sets, upsides, proximity to the Majors and potential immediate impact to their teams. The list, which is one of several prospect rankings on MLBPipeline.com's Prospect Watch, only includes players with rookie status in 2015. Team-by-team Top 30 Prospects lists for 2015 will be unveiled in March.
Stephenson, who was ranked at No. 19 last season, struggled at times last year and went 7-10 with a 4.74 ERA in 27 games, including 26 starts for Double-A Pensacola.
The Reds' first-round selection (27th overall) in the 2011 Draft, the 21-year-old Stephenson walked 74 and struck out 140 over 136 2/3 innings. His power arm produces fastballs generally in the 93- to 98-mph range but can reach 99-100 mph.
Stephenson will be in Reds big league camp for the second straight year this spring as a non-roster invite. He turns 22 on Feb. 24.
Winker, 21, was not ranked in the Top 100 last year, but he turned in some strong numbers amid injuries. Beginning with Class A Advanced Bakersfield, he batted .317/.426/.580 in 53 games with 15 doubles, 13 home runs and 49 RBIs while also missing time with a concussion.
A promotion to Double-A Pensacola followed and the lefty-hitting Winker batted .208/.326/.351 with two homers in 21 games before he sprained a ligament in his right wrist during a car accident. Winker did not play again from July 17 until after the season in the Arizona Fall League, where he owned a league-leading .338 average and .999 OPS with three homers and 18 RBIs in 19 games.
"My wrist felt good out there," Winker said recently. "It was nice just to be healthy and able to play. I was healthy throughout the Fall League. It was a fun time and I'm just looking to keep it rolling."
A first-round compensation pick (49th overall) in the 2012 Draft, Winker could begin 2015 back at Pensacola. But he's been viewed as someone that could reach the Majors in left field with the Reds sometime in '16.
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.