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Sleeper Rookie Pitchers Flying Under the Radar

Who are the sleeper rookie pitchers who could breakout in 2023?  We all know the names of the big pitching prospects who could breakout in 2023.  Grayson Rodriguez…  Hunter Brown…  Cade Cavalli…  Those types of pitchers making an impact in 2023 won’t come as a surprise.  What about the names we may not know?  What about the sleepers (think those outside the Top 100) who could emerge and ultimately provide an elite fantasy impact in 2023?  Let’s take a look:

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Sleeper Rookie Starting Pitchers Flying Under-the-Radar

Luis Ortiz – Pittsburgh Pirates

Ortiz was basically a two-pitch pitcher upon his arrival in the Majors (16.0 IP), so it’s hard to envision him having long-term success:

  • Fastball – 57.8%
  • Slider – 37.1%
  • Changeup – 5.1%

Prior to ’22, noted that “In addition to the electric fastball he showed off in Bradenton during Spring Training, the Pirates were very impressed with how much improvement he was showing with his changeup, which had been a distant third pitch.”  Unfortunately not much has changed in the past 12 months.  In their recent Top 30 prospect list noted, “His changeup is well behind the other two pitches, and he needs to work to differentiate it if from his fastball more.”

His future rests on the development of that offering.  It will ultimately determine if he can stick in the rotation long-term.  There’s no questioning the strikeout stuff or control (he had a 2.68 BB/9 over 114.1 IP at Double-A).  In the Majors, he averaged 98.5 mph on his fastball and had opposing hitters off-balance (13.1% SwStr%, 34.5% O-Swing%).  He also showed the ability to generate enough groundballs (46.8% in Double-A, 43.9% in the Majors).

Ortiz simply needs enough in his arsenal to keep opposing hitters honest.  Right now he’s still an unknown, but with more exposure, they will catch up with him.

If the third pitch can’t be established, Ortiz could be a future lights-out closer.  For now, he should get an opportunity to start.  In fact, it wouldn’t be surprising to see him win a spot in Spring Training.  Just look at the names filling out the rotation.  Keep a close eye on the news this spring.  Talk of his changeup developing will send his stock soaring.

Ortiz opened some eyes last year, but he’s still a sleeper and worth the risk.

Hayden Wesneski – Chicago Cubs

Wesneski has a chance to claim the fifth starter’s job, with Kyle Hendricks being out helping his chances.  Wesneski’s performance in the Majors, after being acquired from the Yankees, helps support that case (2.18 ERA over 33.0 IP).  There was some luck at play (.244 BABIP, 83.9% strand rate), but there was no questioning the skills.  Forget the 33.0 IP in the Majors, he shined over 110.1 IP at Triple-A:

  • Strikeouts – 8.65 K/9 (12.2% SwStr%)
  • Control – 2.94 BB/9
  • Groundball – 42.7%

Wesneski has the repertoire to keep MLB hitters off-balance, showing five pitches over his 33.0 IP in the Majors.  He was generating more ground balls (47.1%) over that short sample, while consistently fooling hitters (11.7% SwStr%, 34.7% O-Swing%).  He could get more ground balls by featuring his sinker a little bit more, as he threw it just 23.03% of the time.  That would come with other implications, as opponents did hit .300 against the pitch.

He doesn’t throw particularly hard, averaging 92.7 mph on his fastballs (combination of four-seam and sinker).  That’s not the end all, be all, of course.  He needs to learn how to use his repertoire effectively, something that should come with experience.  His one spring appearance has given hope, as he tossed 2.0 shutout innings with 1 BB, 1 H, and 4 K.

Wesneski doesn’t have a huge upside, but he has the skills to put together a solid performance across the board.  He could emerge as a breakout sleeper in 2023.

Drey Jameson – Arizona Diamondbacks

Outside of Zac Gallen, does anyone believe in the rest of Arizona’s rotation?  That means opportunity should be readily available.  While Brandon Pfaadt is going to garner more attention, Jameson could make the bigger impact as a sleeper.

Jameson’s size is always going to be questioned, listed at 6’0” and 165 lbs.  So will his struggles at Triple-A in ’22 (6.95 ERA), though the underlying metrics look better:

  • Strikeouts – 8.61 K/9
  • Control – 3.32 BB/9
  • Groundballs – 48.6%

You wouldn’t think home runs would’ve been an issue, but they were.  A 1.66 HR/9 was ugly, as was a .351 BABIP and 60.9% strand rate.  His height does work against him in terms of HR, but this was extreme.  Getting out of the Pacific Coast League alone will help.  Things should improve, and he looked far better in the Majors.  Over 24.1 IP he posted a 1.48 ERA.  He’s thrived this spring, with 4.0 shutout innings including 3 K vs. 1 BB.

There have been questions about whether or not he can stick in the rotation.  However, his pitch mix is impressive and he continues to prove doubters wrong.’s scouting report had him with five pitches, including a four-seam fastball that touches triple digits.  He’s also shown he can hold up to the workload, throwing 157.0 total innings in ’22.

While he could prove to be an elite reliever, he also has the potential and stuff to thrive in the rotation.  That’s enough to put him on most sleeper or breakout lists.

Chase Silseth – Los Angeles Angels

Silseth made seven starts in the Majors in 2022, pitching to an ugly 6.59 ERA.  It’s not a surprise that he struggled, having skipped Triple-A, but things should improve:

  1. Home runs were an issue (2.20 HR/9) despite a 46.2% groundball rate.
  2. The strikeouts disappeared (7.53 K/9) though he showed upside. His 17.8% SwStr% at Double-A was impressive and even his 10.8% SwStr% and 32.8% O-Swing% in the Majors brings hope.
  3. His luck should improve (.306 BABIP, 69.1% strand rate).

At 6’0” there is the risk that home runs continue to be an issue, though not to this extent.  If he can keep that in check, he has the other skills necessary to succeed.  He’s got the pitch mix to keep opposing hitters off-balance.  That includes a pair of pitches that generated ample swings and misses at the highest level (Whiff% of 16.67% on his slider and 15.33% on his split-finger fastball).

You can argue that the Angels’ rotation is deeper than it has been.  They could utilize a six-man rotation, with the need to protect Shohei Ohtani.  There also are questions, especially with Jose Suarez and Tucker Davidson (if he wins a spot).   The rotation is also rather southpaw heavy, and while that’s not a negative it’s something to consider.

He may never be an ace, but Silseth has the skillset to be a productive fantasy option.  Over the last few rounds there’s more value/upside in him as a sleeper, as opposed to a retread that continues to underwhelm.

Prelander Berroa – Seattle Mariners (Deep Sleeper)

Berroa may be the longest shot of anyone on this list.  He was acquired by Seattle in an under-the-radar ’22 trade, but one that may provide huge value for the Mariners.  He’ll turn 23 years old in April, and while the stuff is electric he’s never shown an ability to control it.  Over 100.2 IP in 2022 he posted an ugly 5.63 BB/9.  Of course, he also had a 12.41 K/9 courtesy of a monstrous 19.6% SwStr%.  He’s continued to show that type of explosive stuff this spring, though also not fully being able to control it.  Over 4.0 IP he had 5 K vs. 2 BB.  That type of ratio would be acceptable.

There’s no questioning his impressive stuff, with a fastball and slider that are both considered elite.  However that leads to another question, and that’s whether or not he has the repertoire to remain a starter.  As per Rich Wilson of Prospect 361:

“Prelander Berroa has one of the best arms in the Mariners system.  He has two double-plus pitches in his fastball that will touch triple-digits and a wipeout slider that is his primary out-pitch.  He rarely throws a change-up, which could ultimately push him to a bullpen role.”

Berroa could easily transition to the bullpen and ultimately emerge as a lights-out closer.  Could you imagine the combination of Berroa and Andres Munoz late in games?

However, there is also a question at the back of the rotation.  Can Berroa figure out his control?  Can he develop that third pitch?  That would at least give him an opportunity to leapfrog someone like Emerson Hancock on the depth chart.

At his age, if things click he could move extremely quickly and emerge as the biggest sleeper of the year.

Sources – Fangraphs, Brooks Baseball, Prospect 361,

Who are your favorite rookie pitchers? Drop some names in the comments below. For more great analysis check out the 2023 FantraxHQ Fantasy Baseball Draft Kit!

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