As expected, the Astros’ trade deadline acquisitions have had their pitch arsenals altered

In 2019, starter Aaron Sanchez employed both a four-seam fastball and a two-seam fastball. In his final outing as a member of the Blue Jays, he used each pitch evenly. Six days later, the righty made his debut for the Astros following a deadline trade. Sanchez threw 48 fastballs during that start. All but two were four-seamers.

It’s emblematic of the Astros’ notorious pitch tinkering under renowned pitching coach Brent Strom. Although an injury prematurely ended Sanchez’s 2019 not long after his Houston debut, he spearheaded a combined no-hitter in his first start, and the fairly extreme alterations in his pitch usage played a key role.

Kendall Graveman, Yimi García and Phil Maton were acquired by the Astros prior to this year’s trade deadline in late July. All three relievers have, perhaps predictably, experienced an overhaul to their respective repertoires.

Since August, Maton is throwing his two breaking balls more often while García has cut down on his four-seamer and slider usage in favor of more sinkers and curveballs.

The changes are unlikely to be coincidental when accounting for the movement of each offering. Per Statcast, Maton’s two breakers, especially his slider, have above-average vertical and horizontal movement, and García’s sinker looks to have quality movement on both fronts as well, unlike his four-seamer.

The results both pitchers have yielded since arriving in Houston have been relatively decent. While he allowed three runs against the Mariners in two appearances (1.1 innings) last week, García posted a 3.12 ERA in August in 8.2 innings with a 34 percent strikeout rate.

The same month saw Maton post uncharacteristic numbers, especially in the strikeout department, but he’s since tossed eight scoreless innings in his last eight appearances, thanks in part to some positive regression.

In regard to Graveman, a few adjustments stick out. Chief among them is his slider. Not just in terms of how frequently he’s now throwing it, but the shape of the pitch itself has apparently changed.

The microscopic sample size notwithstanding, the average velocity on Graveman’s slider has dipped below 84 mph in September, after consistently sitting 86 to 87 in each prior month. With this subtraction in velocity has come significantly more vertical drop.

The whiff rate on Graveman’s slider this season is substantial — nearly 48 percent. As good as the 30-year-old’s fastball is, it could make sense to incorporate his second pitch more. But as for his vaunted upper-90s two-seamer, the Astros have him elevating it in the strike zone, something the Mariners did not do.

The glove side in particular is being targeted, primarily to front door the two-seamer against left-handed hitters. Naturally, Graveman’s first strikeout in a Houston uniform features this exact pitch and location multiple times.

Considering the remarkable stats he produced in Seattle, Graveman may not have needed to make any drastic changes, but few organizations in baseball — perhaps even none — optimize pitchers better than the Astros.

With a postseason berth virtually guaranteed, Graveman, Maton and García will all likely see high-leverage innings of varying degrees during the club’s October run, and their newly-adopted approaches could impact the bullpen’s overall effectiveness.