How Astros’ Ronel Blanco went from pitching depth to All-Star candidate: Three changes that made him an ace

Houston Astros righty Ronel Blanco will attempt to continue his surprisingly effective year tonight against the New York Mets. He will enter the contest with marks that include a 2.34 ERA (169 ERA+) and a 2.32 strikeout-to-walk ratio across 14 appearances.  He’s held opponents to one run or fewer in each of his last three starts, including his most recent appearance versus the Baltimore Orioles.

Blanco, 30, wasn’t supposed to serve as the Astros’ de facto ace. Truthfully, if the Astros had their druthers, he wouldn’t have been part of the rotation at all. Instead, Blanco received the opportunity when it became evident Justin Verlander would miss the start of the season. Blanco took full advantage of the chance, throwing a no-hitter versus the Toronto Blue Jays in his first time out and not yet relenting in the time since. Now, he’s positioned himself to make the All-Star Game. 

Should that come to fruition, it’ll represent a remarkable turnaround for Blanco, who came into this season sporting a 4.78 ERA (89 ERA+) in his first 24 big-league appearances in his first two seasons. Just how has he transformed from an overlookable depth piece to a rotation anchor? 

Here are three factors that help explain Blanco’s ascent. 

1. Deeper arsenal

Prior to this season, it was fair to describe Blanco as a two-pitch pitcher. Across his 17 MLB appearances last year (including seven starts), he threw his fastball or his slider nearly 90% of the time. To date this season, those pitches have a combined usage rate under 70%.

Blanco has used most of that 20% to prioritize his changeup, upping its usage from 9% to 26.5%. (He’s also thrown a greater share of curveballs.) While a lot of pitchers will deploy their cambio only when faced with a platoon disadvantage, that’s not the case here. Blanco has thrown nearly 40% of his changeups when opposed by a right-handed batter. All of that would be window dressing if the results on the pitch were poor. Predictably, Blanco has found great success with his changeup: its .148 average against and 35.7% whiff rate are both the best in his arsenal. 

Blanco’s changeup also grades as his best pitch through the lens of pitch-quality models that incorporate velocity, movement shapes, and the like. Baseball Prospectus’ StuffPro metric, for example, has Blanco’s changeup as the 19th best among starters. That may not sound like a big deal, but think about it…