Riley O'Brien #55
St. Louis Cardinals
- P
- B/T: R/R
- 6' 4"/180
- Age: 30
- Riley Chun-Young O'Brien
- Status: Active
- Born: 2/06/1995 in Seattle, WA
- Draft: 2017, Tampa Bay Rays, Round: 8, Overall Pick: 229
- College: College of Idaho
- MLB Debut: 9/28/2021
- Relationship(s): grandson of Johnny O'Brien
2025 Stats
| G | W-L | ERA | IP | SO | WHIP |
|---|---|---|---|---|---|
| 19 | 1-0 | 2.79 | 19.1 | 32 | 1.24 |
2025 Stats
| G | W-L | ERA | IP | SO | WHIP |
|---|---|---|---|---|---|
| 42 | 3-1 | 2.06 | 48.0 | 45 | 1.15 |
2021 Stats
| AB | AVG | HR | RBI | SB | OPS |
|---|---|---|---|---|---|
| 24 | .167 | 0 | 2 | 0 | .467 |
MiLB Career Stats
| G | W-L | ERA | IP | SO | WHIP |
|---|---|---|---|---|---|
| 196 | 28-25 | 3.49 | 472.0 | 545 | 1.26 |
MLB Career Stats
| G | W-L | ERA | IP | SO | WHIP |
|---|---|---|---|---|---|
| 52 | 3-2 | 3.55 | 58.1 | 59 | 1.42 |
MiLB Career Stats
| AB | AVG | HR | RBI | SB | OPS |
|---|---|---|---|---|---|
| 25 | .160 | 0 | 2 | 0 | .450 |
| Year | AB | R | H | HR | RBI | SB | AVG | OBP | OPS |
|---|---|---|---|---|---|---|---|---|---|
| 2021 MiLB Stats | 24 | 1 | 4 | 0 | 2 | 0 | .167 | .259 | .467 |
| MiLB Career Stats | 25 | 1 | 4 | 0 | 2 | 0 | .160 | .250 | .450 |
| Year | W | L | ERA | G | GS | SV | IP | SO | WHIP |
|---|---|---|---|---|---|---|---|---|---|
| 2025 MiLB Stats | 1 | 0 | 2.79 | 19 | 0 | 3 | 19.1 | 32 | 1.24 |
| 2025 MLB Stats | 3 | 1 | 2.06 | 42 | 0 | 6 | 48.0 | 45 | 1.15 |
| MiLB Career Stats | 28 | 25 | 3.49 | 196 | 66 | 19 | 472.0 | 545 | 1.26 |
| MLB Career Stats | 3 | 2 | 3.55 | 52 | 1 | 6 | 58.1 | 59 | 1.42 |
- Next Game:
Splits
| Duration | W | L | ERA | G | GS | SV | IP | H | ER | BB | SO | WHIP |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Last 7 Games | 0 | 1 | 1.35 | 7 | 0 | 3 | 6.2 | 3 | 1 | 3 | 7 | 0.90 |
| Last 15 Games | 2 | 1 | 2.81 | 15 | 0 | 5 | 16.0 | 10 | 5 | 7 | 15 | 1.06 |
| Last 30 Games | 3 | 1 | 1.91 | 30 | 0 | 6 | 33.0 | 22 | 7 | 17 | 35 | 1.18 |
| Last 3 Games | W | L | SV | IP | H | ER | BB | SO |
|---|---|---|---|---|---|---|---|---|
| 9/28 @ CHC | 0 | 0 | 0 | 1.0 | 1 | 0 | 0 | 2 |
| 9/24 @ SF | 0 | 1 | 0 | 1.0 | 2 | 1 | 1 | 0 |
| 9/23 @ SF | 0 | 0 | 1 | 0.1 | 0 | 0 | 0 | 1 |
2025 :
RP
(42)
More Riley O'Brien
Bats' O'Brien strikes out six batters
Louisville's O'Brien with one of his six strikeouts
O'Brien rebounds with stellar start for Biscuits
Stone Crabs take out Tarpons 5-3
Stone Crabs pitch way to 2-1 win in Lakeland
Helman's walk-off homer sinks Stone Crabs 3-1
Walls home run lifts Stone Crabs past Marauders 3-2
Stone Crabs sweep Bradenton with 3-2 win
Stone Crabs sweep Fire Frogs with 3-0 shutout
Latest Transactions
| Team | Date | Transaction |
|---|---|---|
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June 9, 2025 | St. Louis Cardinals recalled RHP Riley O'Brien from Memphis Redbirds. |
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June 6, 2025 | St. Louis Cardinals optioned RHP Riley O'Brien to Memphis Redbirds. |
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June 5, 2025 | St. Louis Cardinals recalled RHP Riley O'Brien from Memphis Redbirds. |
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May 2, 2025 | St. Louis Cardinals optioned RHP Riley O'Brien to Memphis Redbirds. |
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April 25, 2025 | St. Louis Cardinals recalled RHP Riley O'Brien from Memphis Redbirds. |
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March 15, 2025 | Memphis Redbirds activated RHP Riley O'Brien. |
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March 15, 2025 | St. Louis Cardinals optioned RHP Riley O'Brien to Memphis Redbirds. |
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August 27, 2024 | St. Louis Cardinals recalled RHP Riley O'Brien from Memphis Redbirds. |
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August 11, 2024 | St. Louis Cardinals activated RHP Riley O'Brien from the 60-day injured list. |
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August 11, 2024 | St. Louis Cardinals optioned RHP Riley O'Brien to Memphis Redbirds. |
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July 19, 2024 | St. Louis Cardinals sent RHP Riley O'Brien on a rehab assignment to Memphis Redbirds. |
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July 19, 2024 | St. Louis Cardinals sent RHP Riley O'Brien on a rehab assignment to Memphis Redbirds. |
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May 10, 2024 | St. Louis Cardinals transferred RHP Riley O'Brien from the 15-day injured list to the 60-day injured list. Right forearm flexor strain. |
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March 31, 2024 | St. Louis Cardinals placed RHP Riley O'Brien on the 15-day injured list retroactive to March 29, 2024. Right forearm flexor strain. |
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November 5, 2023 | Seattle Mariners traded RHP Riley O'Brien to St. Louis Cardinals for cash. |
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January 31, 2023 | RHP Riley O'Brien roster status changed by Seattle Mariners. |
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January 31, 2023 | Seattle Mariners invited non-roster RHP Riley O'Brien to spring training. |
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July 26, 2022 | Tacoma Rainiers activated RHP Riley O'Brien. |
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July 26, 2022 | Tacoma Rainiers activated RHP Riley O'Brien. |
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June 30, 2022 | Tacoma Rainiers transferred RHP Riley O'Brien to the Development List. |
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June 2, 2022 | Seattle Mariners sent RHP Riley O'Brien outright to Tacoma Rainiers. |
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May 27, 2022 | Seattle Mariners designated RHP Riley O'Brien for assignment. |
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May 8, 2022 | Seattle Mariners optioned RHP Riley O'Brien to Tacoma Rainiers. |
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May 5, 2022 | Seattle Mariners recalled RHP Riley O'Brien from Tacoma Rainiers. |
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April 17, 2022 | RHP Riley O'Brien assigned to Louisville Bats. |
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April 17, 2022 | Seattle Mariners optioned RHP Riley O'Brien to Tacoma Rainiers. |
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April 13, 2022 | Cincinnati Reds designated RHP Riley O'Brien for assignment. |
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March 27, 2022 | Louisville Bats activated RHP Riley O'Brien. |
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March 27, 2022 | Cincinnati Reds optioned RHP Riley O'Brien to Louisville Bats. |
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October 5, 2021 | Cincinnati Reds recalled RHP Riley O'Brien from Louisville Bats. |
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September 30, 2021 | Cincinnati Reds optioned RHP Riley O'Brien to Louisville Bats. |
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September 28, 2021 | Cincinnati Reds recalled RHP Riley O'Brien from Louisville Bats. |
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May 4, 2021 | RHP Riley O'Brien assigned to Louisville Bats from Reds Alternate Training Site. |
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March 29, 2021 | P Riley O'Brien assigned to Reds Alternate Training Site from Louisville Bats. |
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March 12, 2021 | Cincinnati Reds optioned P Riley O'Brien to Louisville Bats. |
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February 3, 2021 | Riley O'Brien changed number to 84. |
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November 20, 2020 | Cincinnati Reds selected the contract of RHP Riley O'Brien from Chattanooga Lookouts. |
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October 2, 2020 | RHP Riley O'Brien assigned to Chattanooga Lookouts from Reds Alternate Training Site. |
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August 28, 2020 | RHP Riley O'Brien assigned to Reds Alternate Training Site. |
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August 28, 2020 | Tampa Bay Rays traded Riley O'Brien to Cincinnati Reds for LHP Cody Reed. |
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September 9, 2019 | Montgomery Biscuits activated RHP Riley O'Brien from the 7-day injured list. |
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July 26, 2019 | Montgomery Biscuits placed RHP Riley O'Brien on the 7-day injured list. |
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May 7, 2019 | RHP Riley O'Brien assigned to Montgomery Biscuits from Charlotte Stone Crabs. |
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April 1, 2019 | RHP Riley O'Brien assigned to Charlotte Stone Crabs from Montgomery Biscuits. |
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February 23, 2019 | RHP Riley O'Brien assigned to Tampa Bay Rays. |
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September 11, 2018 | RHP Riley O'Brien assigned to Montgomery Biscuits from Durham Bulls. |
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September 5, 2018 | RHP Riley O'Brien assigned to Durham Bulls from Charlotte Stone Crabs. |
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August 26, 2018 | Charlotte Stone Crabs activated RHP Riley O'Brien from the 7-day disabled list. |
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August 10, 2018 | Charlotte Stone Crabs placed RHP Riley O'Brien on the 7-day disabled list retroactive to August 9, 2018. |
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June 23, 2018 | RHP Riley O'Brien assigned to Charlotte Stone Crabs from Bowling Green Hot Rods. |
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June 18, 2018 | RHP Riley O'Brien assigned to MID East Division All-Stars. |
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April 2, 2018 | RHP Riley O'Brien assigned to Bowling Green Hot Rods from Princeton Rays. |
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June 21, 2017 | RHP Riley O'Brien assigned to Princeton Rays. |
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June 20, 2017 | Tampa Bay Rays signed RHP Riley O'Brien. |
+ Show More Transactions
Awards
APP Pitcher of the Week
| Week | ||
|---|---|---|
| 07/02/2017 | Princeton Rays | APP |
| 08/06/2017 | Princeton Rays | APP |
MID Mid-Season All-Star
| Year | ||
|---|---|---|
| 2018 | Bowling Green Hot Rods | MID |
PCL Post-Season All-Star
| Year | ||
|---|---|---|
| 2023 | Tacoma Rainiers | PCL |
League Rankings
Hit By Pitch
| HBP | ||
|---|---|---|
| 2025 | 7 | in NL |
| 2025 | 3 | in INT |