Scouting Report: Riley O'Brien

Summary

Riley O'Brien, 31-year-old St. Louis Cardinals closer, has emerged as an elite relief pitcher in 2026 with a 2.84 ERA, 0.95 WHIP, 23 strikeouts, and 11 saves across 19 innings. The late-blooming right-hander has transformed his career through an overhauled arsenal featuring a 98 mph power sinker and sharp 83 mph sweeper. He ranks third among MLB relievers in fWAR (0.8) and is tied for second in saves. His elite 26.9-29.3% K-BB rate and 1.5% walk rate represent a dramatic improvement from his previous career struggles. However, recent struggles include allowing 6 earned runs and blowing 2 saves over his last 5 2/3 innings, raising questions about his durability in the closer role given his lack of extensive closing experience.