Yilber Diaz Needs to Find Strikeouts, Avoid Base Traffic vs Royals

The D-backs will begin a series against one of the AL's tougher teams in Kansas City.

Diamondbacks pitcher Yilber Diaz (45) celebrates an out in the fourth inning during a game against the Blue Jays at Chase Field in Phoenix on Saturday, July 13, 2024. / Patrick Breen/The Republic / USA TODAY

Fresh off a series win over the Chicago Cubs at Wrigley field, the Arizona Diamondbacks will begin a three-game set with the Kansas City Royals at Kauffman Stadium. The first pitch is at 5:10 PM Arizona time.

The Royals have been one of the stronger American League teams, led by young phenom Bobby Witt Jr. and his .957 OPS, but the true heroes of their 55-45 season have been their pitchers, particularly the starting rotation.

Kansas City has a team ERA of 3.71 and a 3.44 by starters. Seth Lugo, Cole Ragans, and Michael Wacha all sport ERAs in the 3.00s or better.

But the D-backs have a young weapon ready to take the mound tonight. Young righty starter Yilber Diaz took his first two starts with force, going six strong innings each time and allowing just two total earned runs.

Diaz's high-octane fastball can touch 98 MPH, and his slider and curveball have both been effective at multiple levels. Opponents have hit just .195 against him, adding to a 0.92 WHIP.

Diaz has maintained a strong mound presence, pitching around traffic and becoming an immediate contributor to Arizona's injury-ridden rotation, but will face a challenge in this Royals lineup.

His control faltered significantly in his recent start against Toronto, landing only 49 of his 87 pitches for strikes and walking two, while only striking out two. His ability to pitch through traffic has been impressive, but a 93% left-on-base percentage might not be sustainable.

As is often the case, command will be the key to this start. While Diaz's raw results have been excellent, he'll be taking his third turn, with some major league data now at the disposal of opponents.

Part of his minor league calling card was a high strikeout rate. He sported a K/9 north of 11 at both the Double-A and Triple-A levels, but he's only punched out seven batters in 12 major league innings.

He's not generally a soft-contact pitcher, so any number of baserunners will bring a serious threat if he's not able to strike batters out. He has the potential for high regression in his LOB rate.

Considering the Royals' lineup has the trifecta of contact, power, and speed, jams might be harder to get out of unless he can tunnel his breaking pitches well and create deception and whiffs.

Diaz has yet to receive his "welcome to the majors" moment, but, if he's not careful, tonight could be the night. At any rate, both his stuff and mound presence are positive signs, and, at only 23 years old, his ceiling remains high.

Across from Diaz is left-handed stud Cole Ragans. Ragans has been nothing short of elite in 2024, pitching to a 3.16 ERA, but with a 2.66 FIP, worth 3.3 bWAR. He's racked up strikeouts at an exceptional rate, punching out 141 batters against 38 walks in only 116 2/3 innings.

He throws a tough fastball that averages 96 MPH, with a diverse arsenal behind it. He throws a cutter and changeup, but his slider and curveball are his weakness, as his breaking pitches have a -6 run value.

This makes him susceptible to reverse splits, and being more effective vs right-handed bats than lefties. Jack Sommers dove into this in detail here.

With that in mind, the left-handed bats will be crucial for the D-backs. Considering Ragans has only suffered two blowups while pounding out quality starts and going consistently deep in games means they'll have to try and extend at-bats, rather than swinging away.

Creating chaos on the bases will be necessary, as Ragans can easily prevent runners from advancing with his high swing-and-miss. Arizona could have to manufacture offense with some small ball.

Lineups

Arizona Diamondbacks vs Kansas City Royals lineups / Alex D'Agostino

The D-backs will trot out a bit of a different lineup. With Ragans' reverse splits, both Corbin Carroll and Alek Thomas are in the lineup, though Carroll will hit seventh and Thomas ninth. They are the only lefty bats in the lineup, with Randal Grichuk taking DH duties over Joc Pederson.

The ever-dangerous Ketel Marte will lead off, with Gabriel Moreno back in the two-hole behind him. Moreno has had success in that high slot and is slashing .340/.436/.489 with a .926 OPS since June 29th.

Bobby Witt Jr. remains the most dangerous bat in Kansas City. He's slashing .337 /.382/.575, good for a 161 wRC+. He has speed, enough power for 17 home runs, and an all-around solid approach at the plate. The D-backs will have to be very careful with the young star.

Salvador Perez has found an offensive surge. The veteran catcher is hitting .280 with a .343 OBP and equals Witt's 17 homers. His strikeout rate is down a solid 4-6% compared to his previous three seasons, although it does still sit just under 20%, but he's been a menace at the plate in his age 34 season.

Defensively, he's not the strongest, although even those numbers are up from previous years. Arizona should be able to take advantage of his 13th-percentile pop time and create some distractions for Ragans.