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Riley O'Brien played 4 major-league seasons (2021-2025) as a P (52). Career totals and every year-by-year line below come from the SABR/Lahman database (CC BY-SA), covering 1871-2025.
Showing 4 season lines
| Year | Age | Team | G | GS | W | L | SV | IP | SO | BB | ERA | ERA+ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021 | 26 | CIN | 1 | 1 | 0 | 1 | 0 | 1.1 | 2 | 3 | 13.50 | 31 |
| 2022 | 27 | SEA | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0.00 | — |
| 2024 | 29 | SLN | 8 | 0 | 0 | 0 | 0 | 8 | 11 | 8 | 11.25 | 37 |
| 2025 | 30 | SLN | 42 | 0 | 3 | 1 | 6 | 48 | 45 | 22 | 2.06 | 205 |
| Year | Pos | G | GS | PO | A | E | DP |
|---|---|---|---|---|---|---|---|
| 2021 | P | 1 | 1 | 0 | 0 | 0 | 0 |
| 2022 | P | 1 | 0 | 0 | 0 | 0 | 0 |
| 2024 | P | 8 | 0 | 0 | 0 | 0 | 0 |
| 2025 | P | 42 | 0 | 5 | 8 | 0 | 1 |
Team codes are the source codes (e.g. NYN for the New York Mets, BS1 for the 1875 Boston club). OPS+ is league-season normalized, not park-adjusted; unrecorded source values (such as RBI in the earliest recorded seasons) are absent, never zero-filled.
Riley O'Brien is a playable Legends Deck card, rated from real Statcast data and refreshed nightly: view the Riley O'Brien card.
Riley O'Brien appears in 2 archived official MLB transactions (1 trade), newest first.
| Date | Type | From | To | Details |
|---|---|---|---|---|
| Nov 5, 2023 | Trade | Seattle Mariners | St. Louis Cardinals | Seattle Mariners traded RHP Riley O'Brien to St. Louis Cardinals for cash. |
| Jun 20, 2017 | Signed | — | Tampa Bay Rays | Tampa Bay Rays signed RHP Riley O'Brien. |
From MLB’s official StatsAPI transactions feed (2011 to the current season, trades/signings/releases involving major-league clubs). Browse the full archive.
Every career total and season line is computed from the SABR / Sean Lahman baseball database (2025 edition, CC BY-SA 3.0), the same source behind our historical position leaderboards. Rate stats use league-season normalization only (OPS+ and ERA+ as marked, never park-adjusted); unrecorded early-era values stay absent rather than being invented. Career totals sum only what the source records.
Award winners and MVP / Cy Young / Rookie of the Year voting history come from the same database; the year pages live under MLB award voting history. Official transactions (2011 to the current season) come from the MLB StatsAPI feed on our transactions archive.