Romero hit the game-winning home run off of Evan Scribner, a right-hander, but the rest of this post is about left-handers. The Mariners were linked to Nelson Cruz all offseason because Zduriencik let it be known that the team was looking for a right-handed power bat to offset the M's lefty-laden lineup. Stefen Romero has emerged as the best internal option, and emerged enough to potentially claim a spot on the opening day roster.*
*Time for a mea culpa. I totally ignored him as a possibility just over a week ago. Oops.
Now, since Romero doesn't project to play every day, and he would earn a bench spot as the right-handed bat the Mariners feel they need to offset all their lefty hitters, it is likely that Romero's most meaningful action would come as a pinch-hitter against lefty specialists. Essentially, he is the guy tasked with making managers ask themselves what they would rather deal with: one of their premier set-up righties against guys like Brad Miller, Dustin Ackley, Logan Morrison, and maybe even Kyle Seager** - or the lefty specialist against Stefen Romero.
**Cano bats left-handed too, but nobody is pinch-hitting for him, regardless of the situation. Nor should he ever be lifted for a pinch-hitter.
So it would be pretty cool if Stefen Romero can, you know, hit lefties pretty well. I dug into his minor league track record for some answers.
Minor league data is incomplete at best, for many reasons. First of all, there are only small sample sizes for Stefen Romero at each level, and the level matters a ton. Romero hasn't really faced lefty specialists because they don't exactly exist in the minors until AAA, and maybe AA here and there. A pitcher becomes a lefty specialist after they've proven they can't handle other more significant roles (starting and closing/late relief). Baseball Darwinism basically guarantees all specialty lefties are "crafty." If they weren't, they'd be a starter or a closer. Therefore, projecting how Romero fares against specialty lefties is a whole bunch of educated guesswork.
Let's start by understanding what kind of Romero hitter is in general. Here are a couple heat maps from MLBfarm.com showing where Romero's hits go when facing left-handers and right-handers:
Romero has faced many more righties simply because there are more righties in baseball, and that is why the righty heat map is more populated. However, aside from more data points, the two heat maps don't look all that different. The hottest spot on both is the hole between shortstop and third base. There's also a frequent spot for ground balls at second base. There are three frequented pockets ranging from the left field foul line to straightaway center. In all, Romero exhibits a slight pull tendency whether he faces lefties or righties. Unsurprisingly, most of his home runs are to left field too. His approach doesn't seem to change much whether he faces a left-hander or a right-hander.
The heat maps square up with Romero's production so far in the minor leagues. According to splits I obtained at Minor League Central, Romero's career minor OPS against left-handers is .885, while against right-handers .859, a minuscule difference especially when the small sample sizes are considered (along with league and ballpark switches in that time). Moreover, that difference is completely driven by walks as his walk rate against lefties (9.6%) is almost double that of his against righties (5.1%). Everything else is virtually the same, though perhaps you could convince that his K% is a bit different depending on handedness (17.0% vs. L, 15.7% vs. R). That's the biggest gap in his splits though, other than walks.
Romero has essentially been the same hitter in the minors whether he faces left-handers or right-handers, which generally comes in handy. However, it's unfortunately a value that will go unused if Romero mainly gets at-bats as a lefty specialist smasher. So would he still be of value as a hitter only against left-handers, given one of his strengths is his consistency against either hand?
It's hard to say how Romero would fare against lefty specialists. Like most hitting prospects he is a great fastball hitter. Via MLB Farm again, 75% of Romero's hits in pitch F/X parks (a very, very limited sample size in the minors) came on fastballs while just about 35% of his swings and misses came on heaters. Most hitters swing and miss against breaking pitches more often, so that's not an alarming statistic, but it's still there.
Specialty lefties don't throw many fastballs though. They tend to throw loopy breaking balls that are death to lefties because of arm slots that seem to start behind a left-handed hitter and make pitches cut away out of reach of a lefty hitter. However, the same tactics make a ball cut in to righties and don't create that awkward "behind the hitter" effect at all from the right-handed batter's box. Hence why lefty specialists tend to have massive platoon splits.
So, how would a lefty specialist attack Romero? Would he be lost against their breaking ball? Or would their breaking ball be utterly ineffective?
My best guess is that a lefty specialist's stuff is not all that different from what Romero has already seen in the minors. Remember, lefty specialists are never top prospects. They survive on deception, and that is mitigated, if not completely negated, by right-handed batters. Moreover, one thing Romero's higher walk rate against lefties might suggest is that he sees the ball better out of a lefty's hand, which would again hint at negating deception. With that said, Romero struggled mightily against the few left-handers he faced in AAA last year (.679 OPS in 95 plate appearances, versus an .806 OPS against righties in 316 plate appearances), so maybe those slurvy, sweeping breaking balls are death on him.
I am really only certain of one thing right now: Stefen Romero is not destined to be a lefty smasher in his career. If the M's try to turn him into that he will join a graveyard of failed hitting prospects already too large thanks in part to organizational ineptitude. However, breaking Romero into the majors against crafty southpaws could work. There are as many reasons in his minor league stats to think he will fail miserably as there are to believe he will do just fine in such a role. It's at least a question worth answering in the batting cage and spring games through Lloyd McClendon's seasoned eyes.