In 2021, there are three pitchers in MLB who have kicked and dealt at least 100 times and who have thrown one type of pitch more than 90 percent of the time. Unsurprisingly, the four-seam fastball is the weapon of choice for these three pitchers, but in this era of every team having two, three, or even a whole stable full of guys who can throw 98 mph, none of these pitchers are fireballers. There’s Sean Doolittle, who has built a fine career with a fastball in the low-to-mid 90’s. Then Travis Bergen, Toronto’s prodigal son who hasn’t given up a run in eight outings thanks to his 92 mph heater. Finally, there’s Richard Rodríguez whose 93 mph fastball has kept opponents to one run in 17 innings this year.
Predictably, there hasn’t been a lot to cheer about in Pittsburgh. A 17-23 isn’t that bad considering the projections, but a -44 run differential ranks last in the National League and second-to-last in the majors. Worse than that, Ke’Bryan Hayes has been hurt since the first week of the season. Until Hayes returns, the brightest spot on the roster has arguably been Richard Rodríguez who suddenly performing like one of the best relievers in baseball.
Rodríguez looked like a smart breakout pick after a stellar showing in the truncated 2020 season. The then 30-year-old posted a 2.85 FIP in 23 1⁄3 innings, striking out 36.6 percent of the batters he faced while walking just 5.4 percent. If one were banking on Rodríguez taking a step forward, it would be the slider rather than the fastball that would have driven that confidence. In 2020, Rodríguez induced a whopping 63.6 percent whiff rate. Opponents hit just .050/.152/.050 against his slide piece, and he was throwing it with 1.7 more inches of break than the year before.
Instead of following the path of so many others and throwing his breaking ball more often, Rodríguez has effectively shelved it. Though he had thrown the slider a career-high 27.6 percent of the time in what was easily his best season, Rodríguez upped his fastball usage and is only throwing the slider once every 10 pitches on average. So far, he’s been even better.
At least he’s been better by ERA and some run estimators. Before play on Monday, the only pitchers who had thrown more innings with a lower ERA than Rodríguez’s 0.53 mark were James Karinchak and Alex Reyes. Statcast’s xERA has Rodríguez at 1.47 and FIP has him at 1.66.
Throwing mostly fastballs means that a pitcher is going to fill up the zone. Per Baseball Savant, Rodríguez’s In Zone% is currently 55.3, a good 6.5 percentage points higher than it was in 2020. Naturally, his walk rate has plummeted, and it was already great before. His 1.7 percent walk rate has been outshined by the likes of Liam Hendriks, Corbin Burnes, and Gerrit Cole, but it’s still a great mark to start the season.
It’s a double-edged sword, though. More fastballs mean fewer walks but because it’s not a premier swing and miss pitch, it also means fewer strikeouts. A 24.4 percent strikeout rate seems pedestrian compared to last year’s 36.6. That Rodríguez is missing fewer bats likely means that his shiny sub-2.00 FIP isn’t long for the world. That’s hard to maintain even with an elite strikeout rate. Whiffs aren’t everything, though.
His heater only sits 93 mph, but throughout his career, Rodríguez’s fastball has been difficult to square up. In 2021, hitters only have an xwOBA of .187 against the pitch. What it lacks in velo (compared to his peers), it makes up for in horizontal movement. This season, Rodriguez’s four-seamer has averaged 14.2 inches of horizontal break. That’s the most his fastball has ever moved in a season and though that’s likely due to the lighter baseball, it’s still about 95 percent more break compared to similar fastballs. Measured against other four-seamers thrown at about the same speed and from the same release point, Rodriguez’s fastball breaks 6.9 more inches.
So far, Rodríguez’s four-seamer has been the fifth-most valuable heater in the majors at -8 runs. The only fastballs ahead of him all belong to starters. It’ll be interesting to see whether Rodríguez to his new approach. His slider is still deadly, but he hasn’t had to throw it much with how well the fastball has worked. Sometimes simpler is better.
Kenny Kelly is the managing editor of Beyond the Box Score.