Zac Grotz is a right-handed reliever from San Mateo, California, who broke into the big leagues on August 2, 2019 with the Seattle Mariners. Now 33, he’s carved out a second chapter in Caribbean winter baseball — and right now, he’s one of the more interesting arms to watch in the Mexican Pacific League.
Background
Born February 17, 1993, Grotz came up through the American minor league system before earning his MLB call-up with Seattle. A right-handed pitcher and batter standing 6’2″ and 194 lbs, he profiles as a versatile bullpen arm with the ability to generate strikeouts and maintain velocity deep into outings.
MLB Career
Grotz’s debut season in 2019 showed real promise: 17.1 innings, a 4.15 ERA, 18 strikeouts and a 1.27 WHIP — respectable numbers for any pitcher making his first impression in the majors. The 2020 shortened season was a different story. In just 7.1 innings, his ERA ballooned to 14.73, and his path back to a roster spot in the big leagues closed quickly after that.
| Season | Team | IP | ERA | W-L | K | WHIP |
|---|---|---|---|---|---|---|
| 2019 | Seattle Mariners | 17.1 | 4.15 | 1-0 | 18 | 1.27 |
| 2020 | Seattle Mariners | 7.1 | 14.73 | 0-0 | 4 | 3.00 |
Winter League Career
Rather than walk away from the game, Grotz redirected his energy toward winter baseball — and the results have been encouraging. Here’s how his recent winter seasons stack up:
- 2026-27 LMP — Naranjeros de Hermosillo: 2 appearances, 10.1 IP, 0.00 ERA, 1 win, 10 strikeouts
- 2025-26 LVBP — Tiburones de La Guaira: 14 appearances, 63.2 IP, 4.95 ERA, 1-6 record, 64 strikeouts
- 2024-25 LIDOM — Tigres del Licey: 3 appearances, 9.0 IP, 4.00 ERA, 0-1, 4 strikeouts
The Venezuelan and Dominican stints gave him volume and competitive reps. But this winter in Hermosillo is where things are clicking — 10 strikeouts and a perfect ERA through 10.1 innings is the kind of run that keeps a career alive and earns trust in any clubhouse.
The Bigger Picture
What makes Grotz worth following isn’t just the current numbers — it’s the resilience. After a rough 2020 ended his MLB run, he didn’t disappear. He went to work in the Caribbean leagues, logged meaningful innings in Venezuela and the Dominican Republic, and arrived in Hermosillo throwing well. That kind of staying power is exactly what winter baseball rewards.
