Age: 24 yr
Height: 6-2
Weight: 230 lbs
Hits/Throws: R/R
Acquired: 2016 IFA (SD)
RuleV: On 40-Man Roster

Physical Description

Athletic build with a strong foundation. The limbs are long and the shoulders are broad. Excellent mobility. There is no longer any tangible projection.

Delivery & Mechanic

With several moving elements, this is a traditional overhead wind-up. It moves through the motions swiftly, which helps keep the time in check.

Internally rotates the lower half while providing a large layback in the upper half, resulting in increased arm speed. High effort can make it difficult to continuously find a high-3/4 releases.


Currently sits around 92-96, with occasional periods at 99. Velocity has fluctuated throughout the years. Raw spin efficiency appears to be unoptimized, resulting in shape inconsistency.

The release produces a lower-than-average 4-seam axis that flashes in the heavy bore. It’s a solid performer with some room for growth. Ratings:55


On an 11-5 axis with a horizontal break, the numbers range from 72 to 76. Raw spin that is above normal produces good depth, and efficiency that is above average helps retain shape.

Hitters are kept off balance by the FB’s large velocity disparity. Starting out of the zone and breaking in seems to be a stronger suit for him.

To improve the whiff possibility, consider lowering the spin axis to around 6:00. Overall potential is above average, but execution and shape must be improved in order to reach that level. Ratings:50


With an above-average sweep, 83-85 is a good score. Although the movement profile may resemble that of the CB, velocity separation is usually sufficient to justify throwing it.

Could enhance gyro by raising axis or decreasing spin efficiency. Either way, the SL and CB might be separated. Even if it’s his current go-to, it’s a fringe proposition. Ratings:45


With a higher-than-average sink, the score is 85-87. Hitters may struggle to see out of the hand with good arm speed, but an erratic release will hurt feelings.

Will appear to be a solid whiff offering, particularly to LHHs, but will rely on his breaking balls more often than not. The shift is likely to be hampered by his violent delivery, making it a fringe option. Ratings:45

Control and Command

Spotting the FB and tunneling the SL/CB off of it, he’s had occasions where control and command both appear average or even slightly better.

At other he’s out of the zone, giving up free bases at an unacceptably high rate. Given how explosive he is, his mechanical sequencing is quite efficient, which helps him regain control when he loses it. Ratings:Control: 45 | Command: 40


If the Royals want to keep testing him, Bolanos has the pure stuff to start. Due to his command issues, the most likely conclusion is that he will be used as a low-leverage relief option.

Bolaños performance is excellent enough to work, as is leaning on the FB and BB tandem, but a little more tweaking might be a great help in terms of future bullpen effectiveness.




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