Aroldis Chapman is trying to "diversify his portfolio" this spring. (AP)

Reds fire-baller Aroldis Chapman, who's competing for a spot in the crowded Cincy rotation, tossed two perfect innings on Thursday against the Rockies and spotted a healthy percentage of his pitches in the strike zone.

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Also notable was his repertoire. Here's what Reds pitching coach Bryan Price said after Chapman's outing (MLB.com):

"When these guys are going out for an inning or two at a time, it's hard to establish four pitches," Price said. "I really wanted him to focus on mostly fastball-slider. He threw a couple of splits and one changeup. So we're still trying to define that third pitch. With his arsenal, I don't think he really needs more than three pitches to try and master."

Considering Chapman has thrown his change-up maybe five times over his entire career, one change-piece and a couple of splitters in a two-inning stretch marks a significant change in approach. That's to be expected, as Chapman is of course attempting to transition from relief to starting detail.

The first thing to note is that there is such thing as a two-pitch starter. Nolan Ryan, for instance, threw nothing but a fastball and curve until cultivating a change-up and cutter at the age of 39. Of course, almost all of those who have survived as a starter despite a mere pair of offerings have done so with a fastball-curve tandem. Chapman's breaking pitch is a slider, for what it's worth. 

Chapman, though, is trying to gain a purchase on that third pitch. Insofar as his fledgling changeup is concerned, Harry Pavlidis of Baseball Prospectus recently noted that Chapman's change is strikingly similar to his slider in terms of velocity and movement. Unless he's able to refine it a bit more, it may not function as a truly distinct third pitch.

So what of that splitter? Manager Dusty Baker has lavishly praised this pitch of Chapman's before, and, as Price indicates, Chapman called upon it more than once in Thursday's brief effort.

The split, of course, functions much like a changeup, in that it comes in slower and heavier than a true fastball and (ideally) drops sharply as it approaches the plate. One possible concern is that the split-finger typically has a bit more velocity than the changeup, and the wide "velo cushion" between four-seamer and offspeed pitch is necessary in order to disrupt the batter's timing to a sufficient degree. It'll be interesting to see the spring gun readings on Chapman's splitter compared to his newly restrained fastball (he clocked in at "just" 93 on Thursday). If there's too much compression -- i.e., if they're too close together in terms of mph -- then maybe Chapman should set the ball deeper in his fingers and throw more of a forkball. Or, heck, maybe he's already doing that.

In any event, conventional wisdom is generally right on this point: you need that third pitch in order to keep hitters uncomfortable the third and fourth times through the order, and you need something with good vertical break in order to limit platoon weaknesses. That's the challenge for Chapman this spring, and it's one of the "micro" storylines we'll be following as we saunter toward opening day.

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