Vs. Batter Stats
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2025 Stats
W-L
3-1
ERA
2.06
WHIP
1.15
K
45
SV
6
2026 Projections
2026 Fantasy Outlook
O'Brien opened 2025 in the minors, striking out 32 in 19.1 innings at Triple-A Memphis before he was recalled for his first extended look in the majors. The 30-year-old completed a career-high 48.0 innings for St. Louis, tossing his 98 mph sinker nearly half of the time to suppress hard contact and produce a 54 percent ground ball rate. He didn't strike many batters out and walked more than you'd like to see - his 11.6 K-BB percentage ranked 137th out of the 191 relievers who threw 40-plus innings last year - but the Cardinals' flurry of relief pitcher trades opened up high-leverage opportunities for O'Brien. The right-hander closed out 2025 by racking up four of the last five saves for St. Louis. That puts him in the mix for early 2026 save opportunities, particularly if he throws more curveballs (21 percent pitch usage). O'Brien's curve held opposing hitters to a .059 BA (3rd for that pitch type among those who threw 100+ curveballs) and produced a 50.9 percent whiff rate (4th). Read Past Outlooks