Depending on the metric of choice, Robbie Ray ranged from barely above replacement-level to a Top 15 SP last season...
"Southpaw Robbie Ray posted a 4.90 ERA, 11.3 K/9 and 3.07 K/BB rate over 174 1/3 innings for the D’Backs last season, and as ESPN.com’s Sam Miller notes, Ray’s year also served as an interesting test case for the different ways player value is measured. Depending on who you ask, last season Ray was either barely above replacement level (0.7 bWAR from Baseball Reference), one of the game’s better starters (3.0 fWAR from Fangraphs) or a top-15 starter in the game (4.82 WARP from Baseball Prospectus)."
http://www.espn.com/mlb/story/_/id/18114272/miller-going-war-mystery-robbie-ray
"Southpaw Robbie Ray posted a 4.90 ERA, 11.3 K/9 and 3.07 K/BB rate over 174 1/3 innings for the D’Backs last season, and as ESPN.com’s Sam Miller notes, Ray’s year also served as an interesting test case for the different ways player value is measured. Depending on who you ask, last season Ray was either barely above replacement level (0.7 bWAR from Baseball Reference), one of the game’s better starters (3.0 fWAR from Fangraphs) or a top-15 starter in the game (4.82 WARP from Baseball Prospectus)."
http://www.espn.com/mlb/story/_/id/18114272/miller-going-war-mystery-robbie-ray