How good is Daniel Hudson?

In 2017, I watched Daniel Hudson struggle as a member of the Pittsburgh Pirates. He had a 4.38 ERA in 71 games as a reliever for Pittsburgh, but it seemed much worse. When the offseason rolled around and the Pirates unloaded him, along with minor leaguer Tristan Gray and cash, onto the Tampa Bay Rays for Corey Dickerson, Pirates’ fans were ecstatic.

This seemed to be an obviously good move. In hindsight, it still is. Dickerson was good during his brief tenure in black and gold, but Hudson would ultimately be considered an effective reliever.

After Tampa Bay almost immediately released him, Hudson found himself on the Los Angeles Dodgers’ roster, appearing in 40 games for Los Angeles. He threw to the tune of a 4.11 ERA – not much better than his days in Pittsburgh – and a 4.38 FIP, which was marginally worse than what it was with the Pirates.

Prior to the 2019 season, after signing with the crosstown Los Angeles Angels, Hudson was again released. This time he headed north of the border, signing a free agent contract with the Toronto Blue Jays. In classical baseball analysis, this is where Hudson started to see a shift in his production. Over 45 games with Toronto, he commanded a 3.00 ERA – much better than most of anything he’d produced since he started 14 games for the Chicago White Sox nearly a decade prior.

At the trade deadline, Toronto was well out of contention, boasting a lousy 43-67 record, 19 games back of a wild card spot. The Blue Jays needed young talent, so they decided to shop Hudson around. Southeast of Ontario, the Washington Nationals were trying to piece together a run to catch the Atlanta Braves in the NL East, while battling for a wild card spot. Washington sent minor leaguer Kyle Johnston to the Jays in exchange for Hudson.

Hudson pitched in 24 games for the ’19 Nats, managing a low 1.44 ERA. If we trace Hudson back to his Pittsburgh days a couple years earlier, it was hard to miss what he was doing in Washington.

By that point, the Pirates had a transactions sheet nearly as long as their franchise history of players who they couldn’t squeeze the talent out of (Gerrit Cole, Tyler Glasnow, Charlie Morton, among others).

When I saw Hudson’s performance, I was left wondering: What did the Nationals figure out? Then I began to dig into the numbers. Generally, when a player kicks it into gear, there are metrics which we can point to that indicate the how for why they’re performing so well. Typically, we can look at things like spin rate, or perhaps a heavier reliance on breaking balls in conjunction with a properly used fastball.

His 3.53 FIP was good, but there is a fairly large discrepancy between that number and his ERA. On the season (with both Toronto and Washington), Hudson’s FIP was 3.97, while his ERA was 2.47. The discrepancy still existed, even though it wasn’t as exaggerated. But a number that caught my attention was his 2019 xFIP: 5.08. This number, of course, is Hudson’s expected fielding independent pitching number. Essentially, this means Hudson should’ve given up more home runs. Fair enough. But he didn’t. So, what do the other numbers suggest?

Between 2014 and 2018, Hudson’s slider usage steadily increased, taking it from 4.1 percent to just over 40 percent – a massive uptick. The four-seam fastball was on a similar trajectory, except in 2017, when it took a dip. This means in 2018 Hudson relied mostly on fastballs and sliders. Had that been the case in 2019, I wouldn’t have been surprised. But it wasn’t. Slider usage dipped considerably to 23.3 percent, while fastballs increased to 63.3 percent. (The sinker and changeup stayed pretty steady – and low.)

Hudson must have a really effective fastball then, right? And the numbers should corroborate that claim, right? Not so fast.

When comparing the 2017 and 2019 seasons, there weren’t any major changes. The velocity increased by 0.8 miles per hour, which may be enough to change his fortunes but I’m not really buying that narrative. The spin rate went from 2410 revolutions per minute to 2469 revolutions per minute. Perhaps those two slight increases in conjunction with one another can result in a perceived “rising” effect, like we see with other, more prominent pitchers? I’m skeptical of this, as well.

Furthermore, Hudson “put away” an equal percentage of hitters in ’17 as in ’19 with the fastball at 15.5 percent. He also had a higher whiff rate in 2017 than 2019 by three percentage points. The true batting average and slugging percentages were both higher in 2017 than 2019, but the xSLG of 2019 was actually higher than in 2017. In addition to those numbers, the average exit velocity on the fastball in 2019 was four points higher than in 2017. Finally, BABIP: In 2017, Hudson’s BABIP was .313, which is north of the “normal” range for pitchers, which might suggest he was a bit unlucky in 2017. In 2019, that number was .247, which suggests he was quite a bit luckier than most pitchers. This could be a big factor for why he was successful a season ago.

My conclusion is this: Hudson is a serviceable reliever, it seems, but I wouldn’t expect him to replicate his success from a season ago this year or any other year in the future. While his Pittsburgh numbers were likely an untrue account of his ability, his 2019 numbers likely fall within the same category. Just as 2017 was an aberration regarding inability, 2019 was an aberration regarding talent. Over this season and however many he plays in the future, we should expect to see a regression toward the mean.