It’s been exactly one month.
After great controversy regarding the timing, the Reds summoned Nick Senzel to the majors on May 3.
With the second overall pick in the 2016 MLB amateur draft, the Reds had chosen Senzel out of the University of Tennessee. He had hit .352/.456/.595 and stolen 25 bases during his junior season in Knoxville. Senzel was widely regarded the best college hitter available. He had played 160 games at the University of Tennessee, mostly at third base.
Historical footnote: The Phillies used the #1 pick overall that year on California high school outfielder Mickey Moniak. Moniak (21) is now playing for AA-Reading and rated the Phillies #10 prospect. He’s slipped in-and-out of the bottom of MLB top-100 lists.
A few days after being drafted, Nick Senzel signed a $6.2 million bonus. He became the organization’s #1 ranked prospect and soon, a Top Ten prospect in all baseball.
The Reds assigned Senzel the position of third base for rookie ball and low-A in 2016 and for high-A and AA in 2017. In 2018 for the Louisville Bats, Senzel split time between 2B and 3B, and played one game at SS.
Regarding his durability, Nick Senzel played three complete seasons for Tennessee, appearing in 160 out of the 161 games UT played from 2014-16. But as a young professional, Senzel was beset by injuries including a torn tendon in his right index finger (2018) and a sprained ankle (2019). He also suffered two bouts of vertigo, missing the final week of the 2017 season and four weeks in 2018. He missed the 2018 Arizona Fall League due to surgery to remove bone spurs from his left elbow.
In his May 3 Reds debut, Senzel went 1-for-4 with two walks. He started in center field and has stayed there. Manager David Bell has had him bat mostly in the leadoff spot. Since his celebrated introduction, Nick Senzel has played in every Reds game. In fact, he hasn’t missed an inning, including both ends of the May 27 doubleheader.
This post is a detailed report card on Nick Senzel over the past month. It’s a look backward (note past-tense verbs), not a projection. Not only is the sample size minuscule, but the calendar-based endpoint is arbitrary. A couple of bad games could put Senzel below average on metrics where he’s now above average.
On the other hand, Nick Senzel has played in 28 games with 134 plate appearances. We have data. We can either take a peek or ignore it. Let’s look.
We’ll break down Senzel’s offensive skills into contact, plate discipline and power and analyze each part. Then we’ll examine the contribution of speed and defense to his game.
Contact skills are fundamental to hitting. Can the batter hit the ball and with authority?
The average contact rate [Contact%] for a major league hitter this season has been 76 percent, with a swinging strike rate [SwStr%] of 11 percent. Nick Senzel surpassed the league’s overall Contact% with his own of 79.5 percent. His SwStr% was 9.5 percent. So in general, Senzel made above average contact.
On pitches in the strike zone, Senzel was normal. Both his contact on pitches swung at in the strike zone [Z-Contact%] and the league Z-Contact% were 85 percent. On pitches outside the zone, his contact rate [O-Contact%] was 69 percent, higher than league average 62 percent. One explanation could be because he had good plate discipline (more on that later) and only swung at pitches that were close to being strikes. Either way, it was a positive quality.
Senzel’s strikeout rate [K%] is 26.9% while league average was 22.9%.
Senzel’s basic contact skill produced a batting average [AVG] of .267. Major League average was .249.
Another way to measure contact skill for a batter is looking at his Batting Average on Balls In Play [BABIP]. BABIP measures how often batted balls (excluding home runs) fall in for hits. The main variables in BABIP for a batter are defense, luck and talent. The harder a ball is hit, the more likely it becomes a hit. A fast runner can nudge his BABIP a bit higher by beating out the occasional ground ball.
While there are short-term variances in a player’s BABIP due to defensive plays and swings in luck, over a period of time it’s a decent measurement of contact skills. Joey Votto, for example, has a career BABIP of .351, while Jose Peraza’s career BABIP is .301.
The major league average BABIP right now is .295. Nick Senzel’s BABIP in May was .346, which is outstanding.
Here is the spray chart (Baseball Savant) for all the balls Senzel has put in play. Note that he spread his ground balls to both sides of the field. On balls to the outfield, he showed a strong tendency to the opposite field, including three of his four home runs.
Plate Discipline Skills
There are several ways to measure whether a batter has good plate discipline skills. The first is simply looking at his swing-rate [Swing%], namely at what percentage of pitches does the batter swing. The average swing-rate in the majors is 45-46% and has remained steady since 2002.
In his first month, Nick Senzel’s swing rate was average, at 46%.
But a better way to look at plate discipline is measuring the percent of pitches outside the strike zone at which at a batter swings [O-Swing%]. Another term for O-Swing% is the batter’s “chase rate.”
Data from over a million plate appearances since 2008 shows that swinging at the right pitches is positively correlated with batting average, on-base percentage (walks) and hitting for power.
The closer a pitch is to the middle of the strike zone, the better the outcome for the batter. Swinging at pitches outside the strike zone dramatically cuts batting average and power.
So what’s a good chase-rate?
While the overall swing rate in baseball has remained constant, O-Swing% has increased over the past 18 seasons. In 2002, players swung at 18% of pitches outside the zone. Today, that number is 30%, a healthy increase. On the other hand, O-Swing% has leveled off league-wide and remained relatively steady for the past ten seasons.
League-wide, the O-Swing% for 2019 is 30.7%. The Reds as a team are pretty close to that, at 30.9%. They range from Joey Votto (20.7%) and Jesse Winker (26.1%) to Matt Kemp (39.2%) and Jose Iglesias (43.8%).
Nick Senzel’s O-Swing% was a glittering 26.1%. That put him in the top 25% of all major league hitters with at least 120 plate appearances.
One way that discipline manifested for Senzel was his walk-rate [BB%] of 9%. League average was 8.8%. Senzel’s walk rate going back to his days at Tennessee has always been strong. In college, over three years he had a 13.2 BB%. His minor league rate was 10.6 BB%.
When you add Senzel’s batting average with his walk-rate, it produced an on-base percentage [OBP] of .331. League average was .321.
The most common statistic used to measure a batter’s power is the number of home runs [HR] he hits.
Nick Senzel has never been known for hitting home runs. He had 13 in 600 college plate appearances and 28 in 1000 minor league times at the plate. You wouldn’t say he lacked home run power, but it hasn’t been a big part of his offensive skill set. He has 4 homers for the Reds in 125 appearances. If you extrapolated that to a full season (which you shouldn’t), it would be 20-25 homers.
Slugging Percentage [SLG] is another popular measure of power. SLG is calculated by dividing total bases by number of at bats. A single is one base, a double two bases and so on. It credits the batter with extra-base hits beyond home runs. But SLG can be misleading because it does include singles. A batter with 100 total bases produced by 100 singles (zero extra-base power) would have the same SLG as a batter with 100 total bases produced by 20 home runs and 20 doubles. You might prefer the batter with 100 singles, but if you’re out to measure power, there’s no question which of those two batters hits for more of it.
The best way to address this problem is to delete singles from the SLG formula and just measure extra-base hits. To do that, subtract a player’s batting average from his SLG. That eliminates one-base from every hit, leaving only extra-base hits. It produces the statistic Isolated Power [ISO], a pure measure of power.
Here’s a chart that shows ISO for the past 40 seasons. The
Selig Steroid Era is indicated in dark blue. Duly noted there is no clear-cut end to the steroid era. Penalties and testing became gradually more rigorous beginning in 2003. The Mitchell Report published in 2008. The Juiced Ball/Statcast Era is in red, with the early results for 2019 in dark red on the far right. The most recent jump actually began the second half of 2015.
The 2019 major league ISO through May was .177. It’s a long ball era. In contrast, league ISO was .111 at the time of the Big Red Machine. Current Reds range from a low of Jose Peraza (.118) to an otherworldly .431 by Derek Dietrich. Back on planet Earth, a normal high ISO is along the lines of Eugenio Suarez (.260), Anthony Rizzo (.300) or Mike Trout (.304).
Nick Senzel’s ISO was .183, so above league average. In addition to the home runs, he hit six doubles and two triples. Senzel’s major league ISO to date was roughly consistent with his numbers at UT (.176) and the minors (.196).
Another measure of a batter’s power is the percentage of his Hard-Hit balls. League average is 34.3%. Christian Yelich has 55% and Josh Bell has 49%. Eugenio Suarez leads the Reds with 50% and Jesse Winker is second at 43%. Lowest on the team is Jose Peraza at 29% (bottom 5% of the league).
Nick Senzel’s Hard-Hit rate has been 42.4%, comfortably above average.
Comprehensive Batting Measures
Metrics that measure overall offensive contribution through linear weighting of outcomes also show Nick Senzel has been above average.
The weighted on-base average [wOBA] for the league is .317. Nick Senzel’s wOBA was .331. Similarly, his weighted runs created plus [wRC+] (the “plus” means the stat is scaled to a league average of 100) was .102.
So overall, in his first month, Nick Senzel was a few percent better than the average major league batter.
Speed and Base Running
Nick Senzel attempted 8 stolen bases [SB] and was successful 5 times. That success rate (62.5%) was below the rate of 75% at which stolen bases become net positive contributions to run scoring. Getting caught stealing costs a base runner and an out. In an age where home runs generate such a high percentage of runs scored, base runners and outs are far more important than the extra base.
FanGraphs produces a statistic called Base Running [BsR] which measures base running success in addition to stolen base attempts, such as taking extra bases, being thrown out at bases, etc. The number itself represents the runs above or below average the player contributes through base running.
Before looking at Senzel’s number, it’s important to make the point that base running doesn’t really matter much either way in the big picture. In 2018, only one player (Jose Ramirez) had enough BsR to make one win’s worth of difference. At the other end of the spectrum, no player had enough negative BsR to make the difference in even one game.
Nick Senzel’s BsR score is -0.3. BsR is a counting stat, not a rate stat, which means that Senzel having only played 28 games kept his BsR low in either direction for now. The main takeaway is that he’s been thrown out on the bases a few times.
(Matt Habel published a terrific post at Reds Content Plus on Saturday where he looked at where the Reds rate overall in base running and explains what’s happening. Short version: The Reds have been lousy on the bases this year, but not for the reasons you probably think.)
Nick Senzel has played 100% of his major league time in center field, a position he’d never attempted or practiced before this season.
He committed one error [E] in 236 innings. But as we know, errors are a small part of a player’s defense. Range and arm strength are other important measures.
Senzel has a -3 Defensive Runs Saved [DRS] above average mostly due to a negative grade in range. Another popular measure of defense is Ultimate Zone Rating [UZR]. Senzel also has a negative UZR score (-0.9). That’s again due to his range but also the ball he dropped that was hit right to him. He has a UZR/150 score (what his UZR would be over 150 games) of -10.2. That’s bad. Last year, the worst UZR/150 was -24.5. A UZR/150 of -10.2 means Senzel’s defense would cost the Reds 1 game. But a month is too small a sample for the extrapolation to be valid.
Senzel’s arm is rated positive by both DRS and UZR.
Nick Senzel at One Month
Again, this is a one-month snapshot, not a projection or prediction of the future.
In his first month as a major league player, Nick Senzel fulfilled the promise as a hitter that he’d shown in college and minor leagues. He’s stayed healthy. He’s demonstrated above average contact, on-base and power skills. That’s a great combination. His base running has been slightly negative, but inconsequential in context. Senzel’s defense was what you’d expect for playing a new position. He’s been relatively sure-handed but his inexperience playing the position cost him range.
When you look at it all together, FanGraphs puts Senzel’s Wins Above Replacement [WAR] (offense, defense, base running) at 0.4. Baseball-Reference has it at 0.2 with a solid offensive WAR offset by the negative defense.
Nick Senzel demonstrated an impressive and encouraging underlying skill set at the plate. When/if he improves his range in CF or when/if the Reds move him back to his natural position in the infield, his net contribution would be strongly positive. Just as you would expect for a draft pick and prospect of his caliber.
[If 2300+ words and two dozen metrics don’t slake your Nick Senzel fix, check out my companion piece on Senzel published this morning at Reds Content Plus. It goes into detail on Senzel’s batting using advanced stats, including quality of contact, exit velocity, barrels, pull percentage and expected values. It looks at how Senzel is doing against different types of pitches. You’ll also get a healthy dose of spray charts and heat maps. One final thing there, a surprising early handedness split. Become a subscriber at RC+, or better yet, a recognized Insider, and support the writing Matt Wilkes, Matt Habel, Wes Jenkins and I are doing there.]