It’s time to let Joc Pederson face lefties

When a young left-handed hitter is called up to the big leagues, most teams have a decision to make. Do they platoon him to maximize the value of each matchup, or do they let him face same-handed pitchers to encourage his development as a hitter? Context matters a great deal in these situations, of course. The player’s demonstrated minor league aptitude against southpaws plays a large role in the decision, as does each particular club’s record and playoff aspirations. Teams that aren't in a playoff hunt can easily throw their young player out there to gain lefty on lefty reps, but contenders can't so easily sacrifice quality plate appearances at the altar of player development.

Problems arise when young lefties are called up to a contender and not given at-bats against southpaws. Those hitters don’t get the opportunity to prove whether or not it’s a skill they possess or might develop. It should not be a foregone conclusion that young leftit's must platoon. Our very own Zach Crizer looked into this issue with regard to Mets outfielder Michael Conforto. He showed that while many left-handed batters struggle in their early attempts to reverse the platoon advantage, they can improve if given opportunities.

Early in 2016, Dave Roberts was asked why he was platooning Joc Pederson with newcomer Trayce Thompson and insisted that was not the case. He pointed to Pederson’s upcoming start against Rays’ left-hander Matt Moore as an example that his lineups would be based on opposing pitch types rather than just handedness of the matchup. From Doug Padilla’s story for ESPN:

“Certain guys, their out pitch is a changeup; certain lefties, it’s a breaking ball,” Roberts said. “When typically it’s a breaking ball that’s their best secondary, then it’s tougher for the left-on-left, the visual. Guys who have a changeup as an out pitch, typically the left-handers can handle them better.

Pederson made his skipper look good as he would absolutely destroy a 94 mph fastball from Moore that day, banging it off the center field wall 440 feet away.

Here’s the thing though: That was Pederson’s first start against a left-handed pitcher in the 2016 season, and it didn’t come until May 3rd. He wouldn’t start another game against a lefty until June 1st, when he was lucky enough to draw a matchup with Jon Lester in Chicago. That’s a tough ask of someone who doesn’t get many reps against southpaws.

(Disclaimer: The sample sizes in this piece are small, sometimes laughably so. Rather than constantly remind you to take the data with a small sample sized grain of salt, I'll just put the disclaimer here. After all, the point is not to proclaim Joc Pederson a capable hitter against lefties—the goal here is to show that he deserves a shot to face them consistently. In essence, we’re using a small sample size to ask for a bigger sample size.)

It’s true that Pederson had a disastrous second half in 2015, but overall he posted a 91 wRC+ in 129 plate appearances against left-handers that year. Not too shabby for a low-contact free swinger in his first full season of major league action. It might have been the 37.2 percent strikeout rate against lefties that made the Dodgers reticent to give him opportunities in 2016. The acquisition of Trayce Thompson certainly played a role as well. In Thompson, the Dodgers had found a similarly skilled right-handed complement to Pederson who could handle center field without a significant defensive dropoff.

Whatever the reasons for his platooning in 2016, Pederson ended up with just 77 plate appearances against left-handers. Here’s a look at some notable splits for the season:

It’s clear that he crushes righties. The league’s average exit velocity for left-handed hitters facing right-handed pitchers is 88 mph and Pederson blew that out of the water. His high average exit velocity paired with a 16.6-degree average launch angle—also well above the league average (9.6 degrees) for lefties against righties—shows that when he makes contact against righties Pederson will consistently drive the ball with authority. That is evident in his exceptional ISO, wOBA, and wRC+ marks.

While his exit velocity takes a substantial hit when facing left-handers, it is still above the league average (85.6 mph) for lefty-on-lefty matchups and right in line with the overall league average exit velocity. The most significant problem that Pederson sees with his numbers against left-handers is the 10-degree decrease in average launch angle. He has so much power, but it’s totally wasted if he’s putting the ball on the ground.

Baseball Savant

Pederson saw a ground ball rate of 51.2 percent against left-handed pitchers, as opposed to 37.7 percent against right-handers. This problem certainly helps to explain the lackluster ISO, wOBA, and wRC+. It also shows that the BABIP against lefties, while extremely low and indicative of some bad luck, is not the sole reason for his struggles. If Pederson is given an opportunity but can’t begin to elevate the ball against left-handers, then he should probably remain a platoon player.

Aside from his exit velocity being average against lefties, the hopeful takeaway from Pederson’s 2016 splits are that the strikeout and walk rates are so similar. It’s an indicator that there are not wild fluctuations in his plate discipline depending on the handedness of the opposing pitcher. While there are not readily available plate discipline splits on the major sabermetric sites, we can use Baseball Savant to figure it out for ourselves. Here’s the breakdown:

It’s safe to say that few players have had their swing mechanics tinkered with in the last couple of years more than Joc Pederson. As Chad Moriyama of Dodgers Digest documented near the start of spring training in 2016, Pederson and new Dodgers’ hitting coach Turner Ward set out to simplify the swing and make it more compact. Take a look at the bizarre movement of his front foot from an early spring game against the Giants.

A strange tweak like that was presumably a timing mechanism aimed to change Pederson’s overall approach. It was temporary, gone by opening day.

While his swing seems to be in a constant state of adjustment, whatever Pederson and Ward were doing in 2016 seemed to work. He cut his strikeout rate by a couple of percentage points and saw his overall contact rate rise by over eight percentage points. That’s a major improvement, and when you hit the ball as hard as Pederson does, an increased contact rate will have a noticeable effect on your numbers.

Now, back to those plate discipline splits. The heartening takeaway is how similar they are. Pederson is a little less aggressive and is more likely to take a pitch in the strike zone against left-handers. While he also makes less contact against lefties, most of the difference is a decrease in contact outside of the zone. This is optimal, as contact outside of the zone is going to be weaker than contact in the zone; swinging and missing at these pitches is often preferable to hitting something weak in play. With that exception for pitches outside the zone, his improved contact rate in 2016 did show up against left-handers.

So we’ve learned that his plate discipline splits are not all that different, and certainly nothing to be discouraged about. He doesn’t hit the ball as hard against lefties, yet still hits it at a league-average exit velocity. The issue remains that those batted balls are grounders far too often. It’s promising that there seems to be only one glaring weakness as opposed to a number of problems. Having one main thing to focus on would seem ideal if given the chance to face left-handers on a regular basis.

There is one final tweak that Pederson made last year that’s worth noting. Beginning on September 16th he added a facemask to his helmet when facing lefties.

Richard Mackson-USA TODAY Sports

Unlike most players who sport a mask for protection only after being hit in the face, a story from Doug Padilla of ESPN indicated that Pederson’s reason for wearing it was mental:

“I think I will wear it against lefties or something; try to stay on the ball a little longer,” Pederson said after a two-hit game Saturday that included a mammoth home run to right-center field. “I have to do something against them because what I have done isn’t working.”

He continued:

“Just try to (keep your head in), I guess,” Pederson said. “Just try to hit the ball the other way or do something. Change something up, you know?”

He was rather nonchalant about it, but having the mental fortitude to keep your head in and not pull off of the ball is an important barrier to overcome. The mental aspect of the game remains largely unquantifiable, but it stands to reason that an added burst of confidence as the ball comes at you from a more threatening angle might have a tangible benefit when standing in the box. In the milliseconds a batter has to choose whether or not to swing, a flinch—be it mental or physical—will make or break that decision. Check out how Pederson fared once he started wearing the facemask against lefties:

(Disclaimer: I know, I know, there was already a small sample size disclaimer. I wanted to put another one before this table though because the sample size is comically small. Almost so small that I didn’t include it, but I still found it interesting and worth some consideration. We’re all just going to have to bite the bullet and get through this small sample size table together. Have I hedged enough? Alright. Let’s do this.)

It was just 13 plate appearances but holy cow what a difference. It’s also worth noting that in the playoffs, when also using the facemask, Pederson got on base five times in his 15 plate appearances against left-handers.

Is he a true talent 132 wRC+ against lefties? Highly doubtful. But there’s enough promising information in the plate discipline splits and the late season, post-facemask, mental adjustment numbers to indicate that hoping for league-average production against left-handers from Pederson isn’t unreasonable.

The good news for the Dodgers is that they have very little to lose by letting him try to break the shackles of a platoon. Their lineup is among the strongest in baseball and can almost certainly handle an extended trial for Pederson against lefties. Even if he stumbles a little bit they’ll still have his above-average glove in center field everyday.

Let’s see what he’s got! It’s time to free Joc Pederson.