Justin Martinez Throws 104.2 MPH Sinker in Winter Ball
The Diamondbacks reliever recorded the hardest pitch of his career while pitching for Aguilas Cibaenas in the Dominican winter league.
Updated on Nov. 11, 2026 in Baseball
Justin Martinez threw a 104.2 MPH sinker, the hardest pitch of his career, while pitching for Aguilas Cibaenas in winter ball. The pitch came in the seventh inning against Tigres del Licey, with his team trailing 8-6, and was thrown to Chicago Cubs outfielder Kevin Alcantara.
Why it matters
The velocity reading signals that Martinez's arm strength has held up after elbow surgery and a season of limited MLB innings. It also underscores the growing role of his sinker, which has become the more primary of his two fastballs.
Over six winter-ball games for Aguilas Cibaenas, Martinez has allowed four hits, walked no batters, and struck out eight, posting a 0.67 WHIP. His career MLB walk rate is 14.2%, with 69 walks and 145 strikeouts over 111.1 innings.
The players
Justin Martinez
Justin Martinez is a right-handed reliever for the Arizona Diamondbacks who has built a reputation for power pitching and a high-velocity sinker.
Aguilas Cibaenas
Aguilas Cibaenas is a professional winter baseball club in the Dominican Republic's Liga de Beisbol Dominicano.
Arizona Diamondbacks
The Arizona Diamondbacks are a Major League Baseball franchise based in Phoenix, Arizona, and Martinez's MLB club.
The details
Martinez appeared in 15 games for the Diamondbacks last season, pitching 13.1 innings, after recovering from elbow surgery. His 104.2 MPH sinker was recorded by Statcast, and his career averages of 101.6 MPH on the four-seam fastball and 101.8 MPH on the sinker show that the pitch sits near the top of his range.
Timeline
2026 season: Martinez threw the second immaculate inning of Arizona's season.
Tuesday, November 10, 2026: Martinez threw the 104.2 MPH sinker for Aguilas Cibaenas.
Season Trajectory
The velocity reading comes as high-leverage relief arms are increasingly judged on Statcast-measured sinker speed, which shapes bullpen roles and contract value. Martinez's health and command will determine whether he becomes a long-term closer for Arizona.
Fantasy managers tracking relief arms should note Martinez's strikeout and walk numbers, since his 0.67 winter-ball WHIP and eight strikeouts point to strong short-term production. Roster decisions for Arizona's bullpen depend on whether his sinker velocity holds in regular-season play.
The takeaway
Velocity alone does not guarantee results, but a sinker at 104 MPH gives a reliever a dependable out pitch when command holds. Watch the next few winter-ball outings to see whether this reading repeats.
Further reading
For more on the sport's pitching trends, explore our Baseball coverage.
Source note: This article includes information reported by Sports Illustrated.
