Potential Breakout Hitters for Fantasy Baseball - Early Plate Discipline Improvers

April 22, 2023

Eric Samulski profiles some hitters who have improved their discipline in 2023. These players could see an increase in fantasy value as a result.

Early in the fantasy baseball season, it's so easy to overreact to what we see on the field. We want every early home run barrage or max velocity to be a sign of a pending breakout, but the truth of the matter is that a lot of it is just noise less than 20 games into the season.

However, one of the places we can look for early improvement is in plate discipline metrics. A hitter's swing rate begins to stabilize after 50 plate appearances and their strikeout rate will start to stabilize after 60 plate appearances.

Considering many of the regular starters are over 80 plate appearances now, any early gains here could be a sign of a change with the specific hitter, and with contact rate stabilizing at 100 plate appearances, most contact rates are not far behind.

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Why Is Plate Discipline Important?

Well, quite simply, hitters who have a good understanding of the strike zone have a better chance of offensive success. Most hitters are not Vladimir Gurrero Sr., hitting home runs on pitching off their shoetops. Most hitters do the most damage on pitches over the plate, which means being able to work the counts into their favor by identifying balls and strikes and having the discipline to lay off a pitch that they can't drive early in the count, even if it might be a strike.

Below, I've created a leaderboard of three swing-related metrics that should have begun to stabilize at this point: O-Swing% (swings outside of the strike zone), SwStr% (swinging strike rate), and Swing%, the rate at which a player swings. The hope here is to identify hitters who are making the best swing decisions early on in the season to see if we can see whose early success is real or who might be on the verge of a breakout.

Miguel Vargas - 2B, Los Angeles Dodgers

If you look up players that are underperforming their expected metrics, Miguel Vargas' name comes up almost all the time. He's hitting .186 but has a .271 xBA. He's slugging .279 but has a .439 xSLG. He has a .325 wOBA but a .401 xwOBA. When you look at his plate discipline metrics, you can see why.

His 16.1% O-Swing% is one of the best marks in the league among qualified hitters, and his 8.9% SwStr% is also elite. He has a tremendous understanding of the strike zone and makes strong contact when he does swing with an 83.6% zone contact rate.

If anything, he needs to swing more often. His 37.6% swing rate and 67% zone swing rate are both below league average and more akin to the approach of a home run hitter. Yordan Alvarez, Austin Riley, and Matt Olson have similar zone swing rates (but higher overall swing rates) because they're hunting pitches to hit out of the park. Vargas seems to just be a bit too patient in the early stages of his MLB career, which is preferable to being overly aggressive but still not ideal.

Vargas also currently ranks 189th in baseball among qualified hitters with a 3.3% barrels per plate appearance and ranks 124th in hard-hit rate. Those stats haven't stabilized yet, so we don't want to put too much emphasis on them, but I think if Vargas becomes a bit more aggressive in the zone, he can make more authoritative contact.

Overall, this is a "buy low" profile to me with a rookie who has a clear understanding of the strike zone simply being overly cautious as he makes the adjustment to the big league.

James Outman - OF, Los Angeles Dodgers

Outman was one of "my guys" heading into this season, so I'm happy to see him doing so well in April. You might see a 31% strikeout rate and worry that his .281 average is a mirage, but I would caution against that. Outman has an elite 22.0% O-Swing% and also a strong 54% O-contact, so he's not really chasing pitches out of the zone that he can't handle. The 12.2% SwStr% and 79% zone contact are slightly lower than you'd want to see but nothing that sets off alarm bells.

I'd like to see him being a little more aggressive in the zone, but he's a young kid figuring it out, much like Vargas. However, Outman's 55.6% pull rate suggests he's trying to hunt his pitches to the pull side, which is why he has a 19.4% barrel rate so far. I'm not expecting his 21.4% HR/FB rate to continue, but I think Outman could easily post a .270 average this year with strong HR/SB totals.

Ke'Bryan Hayes - 3B, Pittsburgh Pirates

People are writing off Ke'Bryan Hayes in the early part of the season, which is ironic because I'm now buying the dip. Here's the thing, the idea that Hayes was going to come into some power boon was always far-fetched. He's just never been that kind of hitter; however, I believe he's still going to be the average and stolen base asset that people we're hoping for at 3B.

Yes, he's hitting .222, but he has a .290 xBA. He's making elite contact, ranking 8th in all of baseball with an 88.2% contact rate and ranking 2nd behind just Steven Kwan with a 98.8% zone contact rate. His overall plate discipline metrics are right in line with his past history, but his hard-hit rate and fly ball rate are actually up. In fact, his fly ball rate is up 10% and his launch angle is up to 13 degrees. Isn't that what people wanted?

Hayes is not pulling the ball, so the power isn't going to spike, but he still has an elite feel for the strike zone and is making the same quality of contact he always has. He's hitting leadoff for a feisty Pirates team, and I'd be buying if I needed average, runs, and stolen bases.

Yandy Diaz - 3B, Tampa Bay Rays

Speaking of players we want to see hit more home runs. After three years of me saying that "if only he lifted the ball" was an oversimplified piece of analysis and that some players can't make that adjustment, I may have to admit to being wrong when it comes to Yandy Diaz. The Rays' first baseman currently has a 14.8-degree launch angle and 49% fly ball rate, which are massive improvements over what he's done in the past.

That has led to a 17% barrel rate and 56.6% HardHit rate and six home runs. He's not going to keep a 23.1% HR/FB rate, but this may not just be a flukey hot start.

You can also see small glimpses of that in his plate discipline metrics. Almost all of them are consistent with the hitter he's always been, but he has seen a 5% dip in his contact rate and a 3.5% dip in zone contact. It may be nothing, but it may also be the consequence of a player adding more loft in his swing, which causes him to swing through some pitches he's trying to lift.

Either way, Diaz still has the 56th-best zone contact rate in the majors and an elite SwStr% and may now be coming into more consistent power. Don't sell high unless you're getting back a player you really like/trust.

Spencer Steer - 3B, Cincinnati Reds

There's a lot of focus on high-profile prospects like Jordan Walker, Anthony Volpe, and Corbin Carroll, but Spencer Steer is off to a pretty strong start in Cincinnati. The former Twins prospect is hitting .320/.424/.520 with two home runs and six RBI in 15 games. More pertinent to this article, he's also posting a career-high 15.3% walk rate and a career-low 13.6% strikeout rate. So is it real?

For starters, Steer has cut his O-Swing% down to 20.9%, which has given him an elite 5.7% SwStr%. He's also jumped his zone swing% by almost 6% and is now posting a 90.9% zone contact rate, which is 41st-best in baseball. In fact, if you look at those metrics, Steer is basically showing the same, if not better, plate discipline as Yandy Diaz, a hitter who many people regard as having a tremendous feel for the strike zone.

The only concern for Steer is that the increased contact might be coming at the expense of meaningful contact. His barrel rate is up slightly from his short debut, but it's still at just 7.1% and his HardHit rate is just 35.7%. He's also seen an 8% dip in his pull rate, which could either be a small sample size or a player focused more on making contact than selling out for power.

Still, Steer has seen no meaningful change in his flyball rate or launch angle and is hitting in perhaps the best hitter's park in the league, so I'm certainly looking to buy in here.

George Springer - OF, Toronto Blue Jays

George Springer can't catch a break. The veteran is hitting .208 to start the year with a .224 BABIP. His O-swing% is down 5% from last year, and his SwStr% is at a career-low 7.4%. He has the 18th-best zone contact rate in baseball right now and the 25th-ranked contact rate overall. He also has the second-highest barrel rate of his career and has a .483 xSLG compared to a .325 SLG.

The only warning signs for me early on are just that he's not pulling the ball as often as he has in the past and his infield fly ball rates have gone up pretty noticeably while his launch angle is rising. I still think it's a little too early to pay attention to those metrics since they haven't stabilized, so based on his swing choices, contact rates, and barrel rates, I think Springer remains an elite "buy low" target.

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