Lou Albert Trivino (born October 1, 1991) is an American professional baseball pitcher for the Oakland Athletics of Major League Baseball (MLB).
Trivino signed and made his professional debut that same year with the Vermont Lake Monsters where he was 3–4 with a 3.12 ERA in 14 games (ten starts). In 2014, he played for the Beloit Snappers where he compiled a 7–11 record and 5.28 ERA in 27 games (26 starts), and in 2015, he pitched for the Stockton Ports, going 10–5 with a 3.91 ERA and 1.27 WHIP in 89.2 innings pitched.
Trivino spent 2016 with both Stockton and the Midland RockHounds, pitching to a combined 2–4 record and 2.85 ERA in 45 combined relief appearances, and 2017 with Midland and the Nashville Sounds where he was 8–3 with a 3.03 ERA in 68.1 innings pitched between the two teams. The Athletics added him to their 40-man roster after the 2017 season.
In 2019, despite a strong start, Trivino was temporarily demoted from his role as the primary setup man after a stretch of four appearances in which he gave up nine runs (eight earned) in 4.2 innings, causing his ERA to balloon from 2.42 to 4.40. Trivino did not find the same success as the previous season, ending with an ERA of 5.25 in 61 games. In 2020, he recorded an ERA of 3.86 in 20 games.
Trivino began the 2021 season as part of a closer-by-committee arrangement with the departure of Liam Hendriks via free agency. For July, Trivino won the Reliever of the Month Award in the American League.