Sodo Mojo’s Top 40 Seattle Mariners Prospects: Number 5

We are finally inside our Top 5 Seattle Mariners prospects. Today, we take a look at the second-highest ranked pitcher on our Top 40 list.

The Seattle Mariners have a lot of interesting starting pitching options who will either make their MLB debut in 2020 or get their first extended look in the big leagues. Our number 5 prospect will not be one of them, but may not be that far behind. George Kirby is our #5 prospect.

Kirby, the 20th overall pick of the 2019 draft, is a right-handed pitcher from Elon University who stands 6’4″, 205 lbs. When he was selected, Kirby was viewed as a fast-moving, #4 starter who could be in the big leagues in 2 years. But after just one summer of pro-action, that appears to his floor.

Kirby’s pitch arsenal includes 2 fastballs. He can reach 95 MPH with the four-seam fastball but generally sits 91-93 with a heavy 2-seam fastball. Both pitches show good movement and Kirby should be able to get a lot of value from both offerings with the possibility of a velocity bump still in his back pocket.

Kirby backs up his fastballs with a good slider that flashes plus, and a strong changeup that may end up being his best pitch going forward. Kirby also throws a curveball, but it lags behind the other 3 offerings and is currently projected as more of a “get me over” pitch to steal a strike than an actual weapon going forward.

All of Kirby’s offerings play up at least a half-grade more than the raw data suggest, thanks to impressive command and control. Kirby throws a lot of quality strikes and is generally able to command pitches in all 4 quadrants of the strike zone.

In his brief 23 innings for the Everett Aqua Sox, Kirby didn’t walk a single batter while striking out 25 batters. This show of controlling the strike zone isn’t a fluke either. At Elon, Kirby walked just 6 batters while posting 107 strikeouts in 88 innings. He also surrendered just one home run for the Aqua Sox.

Kirby’s a good athlete with a clean delivery. There are no wasted movements in his setup and his throwing motion, which leads to his excellent command and greatly reduces the potential of serious injury.

Kirby will start 2020 in West Virginia or Modesto and could follow a nearly identical path to Logan Gilbert in his development. Expecting to see Kirby with the Mariners in 2020 is asking a lot, but it isn’t out of the realm of possibility to think Kirby could see the big leagues fairly early in 2021. His upside may tap out as a #2 starter, but he is as safe a bet as anybody to be #4 starter in a big-league rotation.

There is a little bit of Rick Porcello in his game and he will move quickly through the system. There aren’t many prospects with a floor as high as Kirby’s who also has a reasonably high ceiling. And for those reasons, George Kirby is our #5 Mariners prospect.