Riley O'Brien

Active

St. Louis Cardinals · Pitcher

Age 316' 4" · 180 lbsThrows Right

FBaseball Overview

At 31, this Cardinals pitcher brings proven save upside after accumulating 20 saves through early 2026, making him a reliable closer option for fantasy managers seeking ERA and WHIP stability with his sub-1.20 ratios. His strikeout production remains solid with 34 K in 34.1 innings, though the 3.93 ERA marks a notable uptick from his excellent 2.06 mark last season, signaling some regression or increased workload volatility heading into the year. The Mid-Season All-Star selection in 2018 reflects past success, and his PCL Post-Season honors in 2023 demonstrate continued development in the minors, but the current-season ERA elevation warrants caution regarding consistency. Fantasy managers should view him as a saves specialist with streaky performance metrics, offering wins and strikeouts as secondary benefits while monitoring whether his ERA stabilizes.

News Updates

Riley O'Brien records 20th save for Cardinals
The St. Louis closer picked up his 20th save of the season in Sunday's 2-1 victory over Miami, allowing no hits or walks with one strikeout over one scoreless inning.
Jun 29, 2026

MLB Pitching

Year	Team	G	GS	W	L	SV	ERA	WHIP	K	IP	BB
2021	Cincinnati Reds	1	1	0	1	0	13.50	3.75	2	1.1	3
2022	Seattle Mariners	1	0	0	0	0	0.00	2.00	1	1.0	1
2024	St. Louis Cardinals	8	0	0	0	0	11.25	2.63	11	8.0	8
2025	St. Louis Cardinals	42	0	3	1	6	2.06	1.15	45	48.0	22
2026	St. Louis Cardinals	36	0	3	3	22	3.72	1.16	35	36.1	12
Career	Totals	88	1	6	5	28	3.61	1.32	94	94.2	46

Source: MLB Stats API · Multi-team seasons show combined totals — click to expand

Minor League Pitching

Year	Team	G	GS	W	L	SV	ERA	WHIP	K	IP	BB
2017	Princeton Rays	11	10	1	0	0	2.20	1.10	40	41.0	17
2018	2 teams▼	25	13	8	4	0	2.75	1.14	103	88.1	42
2019	2 teams▼	20	17	7	6	0	3.16	1.17	107	102.2	44
2021	Louisville Bats	23	22	7	7	0	4.55	1.31	121	112.2	55
2022	2 teams▼	33	1	1	3	0	7.03	1.89	47	39.2	30
2023	Tacoma Rainiers	51	3	2	5	15	2.29	1.22	86	55.0	31
2024	Memphis Redbirds	14	0	1	0	1	1.35	0.98	9	13.1	5
2025	Memphis Redbirds	19	0	1	0	3	2.79	1.24	32	19.1	8
Career	Totals	196	66	28	25	19	3.49	1.26	545	472	232

Source: MLB Stats API · Multi-team seasons show combined totals — click to expand

Game Log2026 season

Loading game log…

Analytics2026 season · via Baseball Savant

Click for year to year changes

FB Velo98.3 mph

Avg Spin2273 rpm

Whiff %26.8%

K %22.9%

BB %7.8%

Hard Hit %39.4%

Barrel %6.1%

xERA4.43

xBA Against0.25

xSLG Against0.378

BA Against0.227

SLG Against0.303

GB%56.0%

FB%17.0%

What These Stats Mean

FB Velo — Average fastball velocity. Harder throwers generate more swings and misses, setting up every other pitch in their arsenal. Velocity is the foundation of strikeout upside.

Avg Spin — Average spin rate across all pitches. Higher spin creates more movement and makes pitches harder to square up — elite spinners run better strikeout and batting average against numbers.

Whiff % — Swings-and-misses per swing. The most direct measure of a pitcher's ability to miss bats and the best leading indicator of strikeout rate.

K % — Strikeout rate per batter faced. The core fantasy pitching stat — high K% means reliable strikeout totals that hold up even in shorter starts.

BB % — Walk rate per batter faced. The primary control metric. High BB% tanks ERA and WHIP and keeps baserunners on constantly. Elite starters typically run below 7%.

Hard Hit % — Percentage of batted balls hit 95 mph or harder against. Low hard-hit% means weak contact, protecting both ERA and the defense behind the pitcher.

Barrel % — Percentage of batted balls barreled against. The most direct home run predictor — low barrel% pitchers rarely give up long balls.

xERA — Expected ERA based on contact quality allowed, removing the effect of sequencing, luck, and defense. Better predictor of future ERA than ERA itself.

xBA Against — Expected batting average opponents should hit based on contact quality. A gap between xBA and actual BA indicates unsustainable luck in either direction.

xSLG Against — Expected slugging allowed based on contact quality. High xSLG against predicts future extra-base damage; low xSLG means the pitcher is genuinely suppressing power.

BA Against — Actual batting average opponents are hitting — a key WHIP component. Check xBA to see if the number is sustainable.

SLG Against — Actual slugging allowed. Captures hits, doubles, triples, and home runs — lower means the pitcher is limiting the power damage he gives up.

GB% — Ground ball rate. High GB% pitchers generate double plays, limit home runs, and keep the ball in the park — great for protecting ERA and WHIP ratios.

FB% — Fly ball rate. High FB% pitchers give up more air contact — dangerous when combined with high exit velocity, less so when contact is soft.

Loading player data...

Year

Team

ERA

WHIP

2021

Cincinnati Reds

13.50

3.75

1.1

2022

Seattle Mariners

0.00

2.00

1.0

2024

St. Louis Cardinals

11.25

2.63

8.0

2025

St. Louis Cardinals

2.06

1.15

48.0

2026

St. Louis Cardinals

3.72

1.16

36.1

Career

Totals

3.61

1.32

94.2

Year

Team

ERA

WHIP

2017

Princeton Rays

2.20

1.10

41.0

2018

2 teams▼

2.75

1.14

103

88.1

2019

2 teams▼

3.16

1.17

107

102.2

2021

Louisville Bats

4.55

1.31

121

112.2

2022

2 teams▼

7.03

1.89

39.2

2023

Tacoma Rainiers

2.29

1.22

55.0

2024

Memphis Redbirds

1.35

0.98

13.1

2025

Memphis Redbirds

2.79

1.24

19.1

Career

Totals

196

3.49

1.26

545

472

232