Riley O'Brien is a Red Diamond 96 OVR Closer card for the Cardinals, part of the 2026 All-Star set in MLB The Show's Diamond Dynasty. He throws right-handed. The card was added to Diamond Dynasty in July 2026.

On the mound, Riley O'Brien works with a 4-pitch arsenal led by a 95 mph Sinker and a 92 mph Slider. His pitching ratings include 99 Velocity, 82 Control, and 99 Break. The profile favors a movement-heavy arsenal built to miss bats. Notable quirks include Outlier I and Break Outlier from a total of 5 quirks.

DiamondOps grades each pitch in Riley O'Brien's arsenal: Slider (S), Sinker (S), Sweeper (S), and Circle Change (A). 3 of them grade S-tier, which is what separates a genuine out-pitch mix from a deep-but-flat arsenal. Its strongest tunnel pairing is the Sinker off the Sweeper, so the two share a release look. Its 99 mph Sinker adds a velocity bonus on top. Arsenal grades are the same at every difficulty — unlike a hitter's OpScore, a pitch mix does not re-weight as you climb.

Riley O'Brien is not currently traded on the open Diamond Dynasty market — cards like this are typically earned through programs or collections rather than bought with stubs.

OpScore is DiamondOps' composite rating of a card's in-game performance value. Riley O'Brien earns an OpScore of 98.9 on Legend difficulty, ranking #145 among all cards and #9 among Closers.