Dynasty Inspection: Willi Castro

Can the 23-year-old shortstop replicate his hot 2020?

Willi Castro does not have a ton of Major League experience, but at just 23 years old, he’s slated to be the Detroit Tigers Opening Day shortstop. The switch-hitter has had a hot start this spring – he has a 1.120 OPS in 27 at-bats –  and combine that with a 2020 where he hit .349, and six home runs in 140 plate appearances and people start to take notice.

Castro’s NFBC ADP has started to climb in recent weeks. Since the beginning of March, his ADP is 225.12. For the month of February, it was 251.44. He’s jumped ahead of super-utility man Chris Taylor and likely leadoff hitter David Fletcher. He’s even leaped ahead of Gavin Lux, who isn’t far removed from being a top-5 fantasy prospect. Those may not be the biggest fantasy names heading into 2021, but they are well-known fantasy names, and it feels like it means something that Castro is going ahead of these guys despite not having much of a reputation.


The Player


Castro signed with the Cleveland Indians as a 16-year-old out of the Dominican Republic in July of 2013. The infielder spent several years within the Cleveland organization as an aggressive hitter that didn’t take many walks but showed flashes of speed and power. He wasn’t cracking Top 100 lists, but he was finding himself in the top 10 or 20 for Cleveland prospects. Castro was consistently young for the levels he was playing in but only posted a wRC+ of 100 or better in one season. The Indians kept moving him up, though, and he reached Double-A in 2018 before being traded to Detroit midway through the season as part of the Leonys Martin deal.

With Detroit, Castro started to find some success in the minors. In 26 Double-A games in 2018, Castro logged a 155 wRC+, hitting .324 to go with four home runs and four steals. He followed that up in 2019 with good production at Triple-A, hitting .301 with 11 home runs and 17 steals in 119 games. Perhaps most notably, his 7.0% walk rate was a career-high. The performance was good enough to earn him a cup of coffee with the big-league team.


2019 v 2020


Castro struggled at the Major League level in 2019. His aggressive plate approach could not translate to any success against big-league pitching, and he struck out more than 30% of the time. The sample was small, though, and in an equally small 2020 sample, he registered a 150 wRC+.

Stat 2019 (30 Games) 2020 (36 Games)
Batting Average .230 .349
SLG .340 .550
wRC+ 63 150
Home Runs 1 6
Steals 0 0

The results couldn’t have been much different. The 2020 version of Castro is one of the best hitters in baseball, while the 2019 version is one of the worst.  Yes, the sample is small, and the 2020 version was helped by a crazy  .448 BABIP, but the results look like two different hitters. Given the nature of these samples, it’s highly likely that the “real” Castro is somewhere between these two extremes, but which one is he closer to?

Stat 2019 2020
BB % 5.5 5.0
K % 30.9 27.1
Swing % 54 55.1
Chase % 39.8 39.3
Zone Swing % 71 73.1

From an approach point of view, Castro made some slight improvements in 2020. Castro remained aggressive at the plate – his swing rate in 2020 ranked as the 19th highest among hitters with at least 100 plate appearances. Although he became even more aggressive in 2020, and this caused his already low walk rate to dip, even more, he swung more often at pitches in the zone and less often at pitches out of it.

These are oh-so-slight improvements, but they are improvements nonetheless. Of course, this is relative – Castro’s chase rate ranked as the 17th worst in baseball, and it’s likely that pitchers will throw him even more pitches out of the zone in 2021 to try and get him to bite. Overall, his improvements in his approach are encouraging, but they don’t fully explain the large difference in the results.

Stat 2019 2020
Whiff % 30.6 30.6
Zone Contact % 77.4 79.7
Chase Contact % 56.5 50.9

Castro’s whiff rate remained exactly the same across his two campaigns. But what is interesting is where those swings and misses happened. The switch-hitter made contact more often on his swings in the zone in 2020 while making less contact on his swings at pitches out of the zone. While his whiff rate remained the same, the fact that he improved his contact rate on pitches in the zone is a positive sign.

These are the pitches in which Castro can do the most damage and while swinging and missing is generally not thought to be a good thing, it’s much better to miss the pitches out of the zone than the ones in it.

Castro’s Swing/Take 2020

Ignoring that the graphic states that Castro is a left-handed hitter when he is actually a switch-hitter, we can see further evidence of him taking advantage of pitches in the zone. Almost all of Castro’s value comes from him swinging and doing damage on pitches over the heart of the plate.

It is worth noting that overall, Castro does also has a positive take run value. While he is an aggressive hitter, he has positive take values in the chase and waste zones. The shadow zone is the only one that gave him trouble in 2020. Unfortunately for Castro, this is also where the highest percentage of pitches are thrown.

This being Castro’s weakness makes sense knowing what we know now – he’s likely swinging and missing at pitches just out of the strike zone, causing his swing run value to be a negative in this area. It seems worth it for the big boost he’s getting over the heart of the plate, but it could be something pitchers try to exploit moving forward.

Stat 2019 2020
Exit Velocity 84.7 85.3
LD/FB EV 86.1 89.1
Max EV 112 109.6

The good news for Castro is that he increased his average EVs during a season where most players experienced a decrease. The bad news is that while he saw a jump in his EV and LD/FB EV, these numbers are still well below average. The average EV was in the bottom 6% of the league. Castro has been hitting the ball harder this spring, so there is a good chance we see an EV jump from him in 2021. It’s another small sample, but in 21 batted ball events this spring,  which includes a 458-foot mash with an EV 0f 110.6, Castro has an 88.3 mph EV. That homer had a higher EV than any of Castro’s BBEs last season and could point to harder contact coming in 2021.

It only takes a quick look at the scatter plot to realize that Castro is a bit of an anomaly. We know his .349 batting average was buoyed by an unstainable BABIP, but his .306 expected batting average and .505 expected slugging, while lower than his actual results, show that it was more than just pure good fortune. So what caused it?

Stat 2019 2020 League Average
Line Drive % 33.8 31.9 25.7
Topped % 26.5 28.7 33.5
Under % 32.4 19.1 24.3
Hard Hit % 25 31.9 35.1
Barrel % 1.5 9.6 6.4

Taking a deeper look at Castro’s quality of contact and it begins to become more clear as to why he had some of the better expected statistics in the league. In 2020, he was better than league average in line drive, topped, under, and barrel rates. Put another way: Castro was one of the best in baseball at squaring up pitches. A look below shows just how consistent he was at making quality contact.

The light green zones in the graphic above are the topped and under zones, and it’s easy to see that Castro was great at avoiding them. Keeping the topped and under rates in check is important – Jonathan Metzelaar’s look at contact rate last year showed that the expected batting average for a topped ball was about .180 and about .070 for an under-hit ball.

Taking it a step further, Castro was one of only 11 players with at least 100 plate appearances to have a topped rate under 30% and an under rate below 20%. The expected batting average for this grouping, which includes Michael Conforto, Corey Seager, and Bo Bichette, was .278, and the expected slugging was .475. The question for Castro is whether or not the drastic improvement in under rate is legitimate or small sample noise. Given that he was a line-drive hitter throughout the minors, I’m inclined to lean toward it being at least somewhat real.

His below-average hard-hit rate makes sense given his EV numbers, but it’s also encouraging that there was an improvement from the year before. If Castro can continue to square up balls like he did in 2020 and hit balls harder in 2021, he should have great success. The graphic above shows that Castro had several balls qualify as “under” and result in outs but were a few mph away from being a “solid” or a “barrel.” If the gains in EV he’s showing this spring hold, some of those flyouts in 2020 will be extra-base hits in 2021.




Castro has had two completely different big-league campaigns to start his career. In 2020, he made some slight improvements to his swing decisions, and it allowed him to consistently square up the ball. The ability to hit line drives gives the switch-hitting infielder a high batting average floor and the potential for even more of a power break out if he’s able to continue to increase his EVs, especially on flyballs. This spring, he has been able to do just that.

Of course, there is substantial risk in Castro’s profile, too. There aren’t many players in the league who can consistently be successful with a walk rate around 5% and a strikeout rate above 25%. It’s a big red flag. If one of these numbers heads in the wrong direction, Castro could become borderline unplayable.

His 2020 swing decision improvements make this seem less likely, but pitchers will also begin to adjust to Castro the more they see him. And if his EVs continue to be low, it puts a lot of pressure on him to be able to consistently square up pitches in order to be successful. At the very least, this type of profile will lead to some very hot stretches and some very cold ones.

From a fantasy perspective, it’s unclear if his speed will be a factor or not. Castro’s sprint speed ranked in the 84th percentile in 2020, and while this was a slight dip from his 90th percentile ranking in 2019, he definitely has the jets to steal some bags. Castro is yet to register a steal at the big league level and was caught in his only two attempts.

He stole 99 bases in 140 attempts in the minors, but that 70% success rate is also misleading – Castro was not an efficient base-stealer in the lower levels. In AA and AAA, though, Castro logged 35 steals in 44 attempts, which is good for about an 80% success rate. All of this is to say that there could be some hidden stolen base value here. It’s not something to count on at this point, but if first-year manager A.J. Hinch elects to run more than the previous regime, it wouldn’t be surprising for Castro to finish the year with double-digit steals.

As mentioned at the top of the article, Castro’s ADP is on the rise, and it’s clear as to why. From a production standpoint, the best-case scenario is something similar to Lourdes Gurriel, Jr – someone who doesn’t walk much and strikes out at a high clip but could be a high-average, high-power bat with some speed. He’s currently slotted in as Detroit’s starting shortstop, but he played some third base last season and could bounce around the diamond a little bit and have some positional flexibility, too.

As for dynasty leagues, the buying window for Castro is right now. Although his  2021 ADP is on the rise, he’s still a relative unknown going in the mid 200s. The price for him in a dynasty league shouldn’t be all that much. That could change in a few weeks if he continues his hot spring into the regular season. Castro turns 24 in April, has an everyday job at a premium position, and has the potential to breakout. There is a very real bust risk, but the price is low enough right now to take the gamble for the hopes of a big payoff.


Photo by Zach Bolinger/Icon Sportswire | Adapted by Jacob Roy (@jmrgraphics3 on IG)

2 responses to “Dynasty Inspection: Willi Castro”

  1. Dave says:

    Vincent, great read! Looking at the slight increase in topped % and huge drop off in under %, I wonder if there was a significant change in the distribution of pitch types he saw between the two years and how he performed against each type each season. It might explain at least some of the performance improvement. Thanks

    • Vincent Ginardi says:

      Dave – thanks for the kind words. Looks like you are onto something here. Castro saw 18% breaking pitches in 2019 and that jumped to 28% in 2020. Could definitely lead to more topped balls and fewer unders. These were the types of pitches he struggled most against (.268 xBA and .314 xSLG), relatively speaking, so we could see this tick up even more in 2021. I might do a midseason Castro article to see if there are any significant changes.

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