Platoon splits play a key role in how teams set and use their lineups as they aim to squeeze the most production out of players and strategize to play the matchups at key moments.
These numbers sometimes can be overemphasized, relying on small samples to make assumptions about what hitters and pitchers can and cannot do. Just because, say, a left-handed batter hasn't hit lefty pitchers so far doesn't mean he is incapable of doing so.
With that said, these splits can be helpful in illuminating players' strengths and weaknesses. Here is a closer look at 10 notable players -- five hitters and five pitchers -- who have especially wide platoon splits.
Hitters
Nolan Arenado, RHB, Rockies
Career OPS: .842 vs. RHP, 1.008 vs. LHP
With Arenado or any other Rockies player, the focus is always on home/road splits. But Arenado's platoon splits are interesting, too, even as they have fluctuated quite a bit over time. Since the start of 2017, Arenado has mauled southpaws to the tune of a .392/.461/.790 slash line, with an MLB-high 31 home runs in less than 400 plate appearances. His .269/.340/.493 line off righties during that time is tame by comparison, so that's one aspect of his game Arenado could seek to bolster in his final season before free agency.

Eric Hosmer, LHB, Padres
Career OPS: .826 vs. RHP, .669 vs. LHP
Hosmer has the third-most plate appearances against lefties (1,687) since his debut 2011 season, and his OPS ranks third lowest among the 31 lefty hitters with at least 1,000 such plate appearances during that time. Hosmer did top the .750 mark in those matchups in both '13 and '17, but he hit an unsightly .179/.240/.287 in his first year in San Diego last season. That was enough to obscure the fact that Hosmer's .293/.368/.462 line off righties was an almost perfect match for his career numbers. Given that Hosmer signed an eight-year deal last winter, his ability to at least hold his own against same-side pitching will be something to watch.
Kyle Schwarber, LHB, Cubs
Career OPS: .858 vs. RHP, .608 vs. LHP
When Schwarber burst into the Majors in 2015, he produced a .953 OPS against righties, compared with .481 against lefties. But while Schwarber's numbers off southpaws have improved since then, he's been nowhere near as dangerous in those matchups. Even though Schwarber reached base at a .352 clip versus lefties last season, he slugged .303, and 66 of his 72 career homers have been hit with the platoon advantage. Schwarber's entire big league track record against same-side pitching consists of just 250 plate appearances, so perhaps he could turn it around -- if given the chance. The Cubs started him in just 10 of their 35 matchups against lefty starters last year.

Enrique Hernandez, RHB, Dodgers
Career OPS: .665 vs. RHP, .847 vs. LHP
Hernandez is a great example of how a player can come to be defined by his splits, and then turn the tables on that narrative. Through 2017, the versatile defender produced an anemic .207/.265/.324 line against righties that helped limit his playing time despite his success against lefties. Last spring, Hernandez expressed frustration at how he'd been labeled, then went out and hit better without the platoon advantage (.833 OPS) than with it (.780), making more contact and hitting the ball harder. That improvement helped Hernandez blow past his previous career highs in starts and plate appearances, although it remains to be seen if that will become a trend.
Joc Pederson, LHB, Dodgers
Career OPS: .842 vs. RHP, .583 vs. LHP
Pederson didn't set the world on fire against lefties in his 2015 rookie season (.216/.295/.397), but his line has only deteriorated in the three years since (.163/.250/.271). Yet those numbers reflect a total of less than 200 plate appearances, as the Dodgers have used their depth and platoon-heavy approach to limit Pederson's exposure. While he saw about 22 percent of his plate appearances against southpaws as a rookie, that was down to about 13 percent in '18. That likely has helped Pederson produce stellar overall numbers, but if the Dodgers do make the 26-year-old available in the wake of signing outfielder A.J. Pollock, clubs will have to consider whether they view him as an everyday player.

Pitchers
Marco Estrada, RHP, A's
Career OPS allowed: .754 vs. RHB, .689 vs. LHB
Splits don't always go the way they're supposed to. Estrada, a 35-year-old veteran who just signed on to help a thin Oakland rotation, is one example. Using his stellar changeup heavily, Estrada has long been able to handle left-handed batters, limiting them to an OPS very similar to those allowed by the likes of Johnny Cueto, Felix Hernandez and Corey Kluber. Righties have been more of an issue, especially over the past two seasons, when they've slashed .296/.362/.528 with 34 homers. Moving from Toronto to Oakland might not affect Estrada's reverse splits, but it should be good overall for a pitcher who allows a ton of fly balls.
Max Scherzer, RHP, Nationals
Career OPS allowed: .579 vs. RHB, .718 vs. LHB
It's not as if Scherzer isn't good against same-side hitters. That was more of an issue early in his career, as they posted a .269/.346/.440 line against him in his first six seasons. However, going back to Scherzer's breakout 2013 campaign that resulted in the first of his three Cy Young Awards, they have managed a modest .223/.288/.385. Yet that's still well behind his utter dominance of righties (.175/.218/.300). No other starter can touch those numbers, and few relievers can, either.

Julio Teheran, RHP, Braves
Career OPS allowed: .611 vs. RHB, .781 vs. LHB
Teheran has made at least 30 starts in six consecutive seasons and is a two-time All-Star, but his 104 ERA+ since 2015 speaks to a solid pitcher who perhaps hasn't reached the ceiling some envisioned. What's held him back? Among the 56 righty pitchers who have faced at least 1,500 lefty batters since '13, only five have given up a higher OPS than Teheran. Only James Shields has allowed more than Teheran's 86 homers. His National League East matchups with Bryce Harper spoke to this issue, with Harper going 18-for-40 (.450) with eight homers and a 1.702 OPS.
Danny Duffy, LHP, Royals
Career OPS allowed: .769 vs. RHB, .563 vs. LHB
Duffy is in some ways a mirror image of Teheran. Over the past five seasons, left-handed-hitting batters have been basically helpless against him, slashing .201/.250/.262, with just five homers in more than 600 plate appearances. No starter in baseball has surrendered a lower OPS to lefties during that time, with Chris Sale ranking right behind him. Righties, however, have produced at least a .760 mark against Duffy in each of the past four seasons.

Pat Neshek, RHP, Phillies
Career OPS allowed: .543 vs. RHB, .732 vs. LHB
Neshek represents the many relievers with heavy splits who fit quite well in this era of increasing bullpen specialization. The 38-year-old, with his funky sidearm delivery and slider-heavy repertoire, has put together a solid career (2.74 ERA) by annually shutting down righties. Those same-side hitters have just a .490 OPS against him since 2016. But Neshek has been more up and down in his battles with lefties. In his two All-Star seasons ('14, '17), he silenced lefties almost as well as righties, but in three of the past six years, they have tagged him for a .900-plus OPS.