Rookie Starting Pitchers Worth Buying Into

With pitchers going on the DL everyday and some struggling, it's never too early to start looking for their replacements.

Rookie starters are not known for their consistency, to say the least, and may scare fantasy owners away. There are, however, a few names that are worth holding onto this season. A few of these prospects have already made MLB starts, while others are still in the minors.

When looking at waiver wire pickups, here are three rookie SP you should consider giving a roster spot.

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Rookie Pitchers to Believe In

Jack Flaherty, St. Louis Cardinals

Although he is probably rostered in most competitive leagues by now, check on Jack Flaherty. With Carlos Martinez on the shelf and Adam Wainwright on the 60-day DL, Flaherty is one of the Cardinals' top SP options.

His four-seam fastball has averaged 92.3 MPH in 2018, and he throws a slider, two-seam fastball, curveball, and change-up. According to Baseball Savant, his four-seam fastball has a perceived velocity of of 93.4 MPH. His slider has ranged from 80-85 MPH, and it has hitters chasing it out of the zone with a 27.4 SwStr% and 42.1 O-Swing%. Mixing in his two-seamer (57.1 GB%) keeps the ball on the ground, as the right-hander owns a 46.2 career-GB%.

Even though he may not offer the strikeout upside of other rookie pitchers, he improved his control in the minors in 2017. Flaherty owns an 8.3 career-K/9, and four projection systems on Fangraphs project an 8.3-8.5 K/9 for 2018. He lowered his walks to 2.5 BB/9 in AAA, and Steamer projects league-average control for 2018 while ZiPS is more optimistic with a 2.9 BB/9 projection.

In five Triple-A starts, Flaherty has improved his numbers. He increased his K/9 to 11.7 while lowering his BB/9 to 2.0. While it's a small sample, he has carried over that success over to his three MLB starts during the first two times through the order. As expected, his strikeouts (11.2 K/9) have been the highest the first time through the order. As hitters see him for a second time, his strikeouts have fallen (4.0 K/9) and his WHIP has increased from 0.88 to 1.20.

As far as splits go, he has had success against right-handed hitters with .291 wOBA and .658 OPS. Left-handed hitters have hit the ball with authority and a 43.3 Hard% against him. He has allowed five HR in 37 career-IP, and left-handed hitters have hit four of them. He has not fared as well against LHB, as they own a .370 wOBA and .871 OPS against him. During his 2017 in AAA, Flaherty allowed four HR with a 1.56 ERA in 40.1 IP vs. LHB.

If looking for floor, Flaherty is a solid target with his improving control.

Freddy Peralta, Milwaukee Brewers

While Freddy Peralta doesn't have the control of Flaherty, he has the strikeout upside that fantasy owners target. The 5'11" right-hander posted a 12.9 K/9 in AA in 2017 and an 11.9 K/9 in five AAA starts in 2018. In his electric debut at Colorado, Peralta relied upon his fastball with many grips to miss bats (16.9 SwStr%), as he threw 89 fastballs. He made an impression by striking out 13 hitters in 5.2 IP while mixing in eight curveballs.

In his first MLB start, his fastball velocity ranged from 87-95 MPH, but it was only in the zone 51% of the time. Striking out twelve batters shows his upside, but watch to see if he can locate the fastball against Minnesota in his second start on Saturday.

One downside in his profile is his control issues in the minors, which could lead to WHIP inflation on a roster. Peralta owned a 4.9 BB/9 in A and a 4.4 BB/9 in AA/AAA. His WHIP projections range from 1.37-1.62, which all are above league-average.

As he has risen through the minor leagues, he has increased his ground ball rate at each level. He has moved from 36.6 GB% in A to a 53.6 GB% in AAA.

Steamer projects a 4.03 ERA for Peralta with a 10.9 K/9, 4.8 BB/9, and 1.37 WHIP for 2018.

Alex Reyes, St. Louis Cardinals

Much like Peralta's profile, Alex Reyes offers strikeout upside and control can be a problem at times. His pitch mix features a four-seam fastball that can touch 100 MPH, a knee-buckling curveball that ranges from 75-81 MPH, and a change-up that splits the difference (88 MPH) between the two.

Currently, his future role is more muddled, as the Cardinals could use him as a SP or RP. Because of his upside, he is rostered in 72% of CBS leagues.

During his 2016 stint in St. Louis, his change-up missed bats at a 21.5 SwStr% and his slider and four-seam fastball were both over a 10.3 SwStr%. His electric stuff can add plenty of strikeouts to a roster as a SP or RP. Although he missed the 2017 season with Tommy John surgery, he looked strong in his first minor-league rehab start. On May 14, Reyes only allowed one hit in five scoreless IP while striking out 12 batters.

In 342 career-IP in the minor leagues, Reyes owns a 3.41 ERA and 1.30 WHIP with 467 strikeouts.His ground ball rates have ranged between 38.5% and 45.2% in the minor leagues. With a WHIP that's close to league-average, we can expect about the same once he arrives in St. Louis. Steamer projects a 3.63 ERA and a 1.30 WHIP in 78 IP.

Reyes has the highest long-term upside of the three SP, but his 2018 value may depend on his role.

Other Names

If looking deeper, Sandy Alcantara (SP, MIA) and Kolby Allard (SP, ATL) are speculative plays. In eight GS in Triple-A, Alcantara has posted a 3.52 ERA and 1.28 WHIP. He should be available as a stash in most leagues, as he's only owned in 7% of CBS leagues. During his career, he has posted 402 strikeouts in 415 IP with a 3.90 ERA and a 1.33 WHIP.

Kolby Allard has pitched well in AAA with a 1.71 ERA (3.17 FIP) and 1.07 WHIP in seven GS. Even though the Braves have other options like Luiz Gohara, Allard could see some IP if injuries arise. He doesn't offer the strikeout upside of some other SP, as he has a 6.8 K/9 in AAA, and projections have him around a 7.3-7.5 K/9 in the majors. He has kept the ball on the ground with a 44.5 GB% in 2018. Currently, he is owned in 11% of CBS leagues.