When the Mariners drafted Mississippi State switch-pitcher Jurrangelo Cijntje 15th overall in 2024, he captured the imagination of the baseball world. We had seen ambidextrous pitchers throwing from both the left and right sides before, but none with Cijntje’s raw power and legitimate starter traits.
The road ahead was improbable, but at the very least, it made for a fascinating story. Cijntje had found success switch-pitching in the SEC, and many wondered whether the Mariners and their vaunted pitching development could do the impossible: develop a switch-pitcher capable of getting outs as both a power righthander and a crafty lefty.
The experiment took different forms over two professional seasons. Seattle’s early plan was to use Cijntje primarily as a righthander in starts, then have him make lefty-only relief outings in between. The Mariners dropped that plan by May 2025 and instead had him face one to three batters lefthanded per outing. The results were mixed: a 4.58 ERA, 4.33 xFIP and 15.3% K-BB% over 74.2 innings with High-A Everett.
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Cijntje finished the 2025 season in Double-A, where most of his work came righthanded. In two righty-only starts with Double-A Arkansas, he struck out 33.3% of batters and walked 5.6% over 8.2 innings. Throwing righthanded in Double-A overall, he posted a 2.53 ERA with a 26.3% strikeout rate, 9.8% walk rate and .574 opponent OPS.
The results hinted at a crossroads heading into 2026.
| Level | Side | Games | PA | K% | BB% | HBP | HR |
| 2025 High-A | L | 19 | 50 | 14% | 32% | 3 | 2 |
| R | 16 | 265 | 28.70% | 7.20% | 8 | 12 | |
| 2025 Double-A | L | 5 | 12 | 17% | 25% | 2 | 0 |
| R | 7 | 133 | 26.30% | 9.80% | 2 | 1 |
After the season, the Mariners announced they would develop Cijntje as a righthanded-only pitcher. That plan lasted only a few weeks before Seattle traded him to the Cardinals with outfielders Tai Peete and Colton Ledbetter for Brendan Donovan. In St. Louis, Cijntje got another shot at switch-pitching.
He opened 2026 at Double-A Springfield, posting a 5.04 ERA over 17 starts and 80.1 innings. He struck out 28.2% of batters but walked 11.3% and gave up home runs at a high rate. He faced 21 batters lefthanded in Double-A, walking 29% and hitting two. His righthanded numbers were far better, including a 28.2% strikeout rate and 10.2% walk rate.
Promoted to Triple-A Memphis after the all-star break, Cijntje had a rough landing. Over his first four starts, he allowed 16 earned runs in 18 innings, walking 16 and striking out 21. He was still switching throwing hands on the mound, but his lefty matchups produced little more than walks (17%). At that point, the Cardinals dropped switch-pitching and committed to developing Cijntje as a righthanded starter.
The before-and-after results speak for themselves. Over the final six weeks, Cijntje was as hot as any pitcher in the International League. In his first righthanded-only start, he struck out 11 while sitting 96.3 mph and topping out at 97.9.
- Before (July 19–Aug. 6, righthanded batters faced only): 81 batters, 24.7% K, 18.5% BB
- After (Aug. 13 onward): 143 batters, 28.7% K, 7.7% BB
Strong underlying indicators supported the results. Cijntje’s stuff and strike-throwing both improved over his final seven starts as he mixed five pitches: a four-seam fastball, sinker, slider, sweeper and changeup. His changeup usage climbed after he stopped switching, reaching 15% over that stretch.
| Pitch | Use | VELO (MAX) | IVB/HB | nSTF+ | Stuff 20–80 | Whiff% | CSW% | Zone% | xwOBAcon | RV/100p |
|---|---|---|---|---|---|---|---|---|---|---|
| Four-seam | 45% | 96.4 (99.1) | 15.5 / 8.3 | 110 | 60 | 22.8 | 30.5 | 65 | .270 | 3.7 |
| Slider | 25% | 86.0 (90.8) | 3.3 / −5.7 | 115 | 65 | 40.5 | 35.2 | 44 | .280 | 0.3 |
| Sweeper | 8% | 83.6 (87.1) | 3.5 / −13.4 | 120 | 70 | 31.8 | 15.7 | 35 | .200 | 0.5 |
| Change | 15% | 87.6 (90.3) | 8.1 / 14.3 | 105 | 55 | 30.2 | 24.5 | 37 | .280 | −0.5 |
| Sinker | 8% | 94.5 (97.3) | 11.5 / 14.6 | 103 | 50 | 17.2 | 32.7 | 58 | .300 |
Four of Cijntje’s five pitches held hitters to a .280 xwOBA on contact or lower. His fastball zone rate jumped to 65% with a 30.5% CSW%. His sweeper gave hitters a different look from his primary short slider. Both breaking balls generated whiffs and graded out with positive run value, though each works best as a chase pitch.
The changeup is still a work in progress and needs more vertical separation from his fastball. Even so, it showed it can produce whiffs and chases. And if he can land it in the zone more often, it could become a real weapon.
In the end, the numbers make the case: Throughout Cijntje’s pro career, switch-pitching has hurt him more than it has helped.
Here’s a look at data from starts in which Cijntje didn’t throw lefthanded:
| Split | GS | IP | ERA | K% | BB% | K−BB% | HBP | HR | Opp. OPS | WHIP |
|---|---|---|---|---|---|---|---|---|---|---|
| No lefty used | 13 | 62.1 | 3.90 | 28.10% | 8.00% | 20.20% | 3 | 6 | .668 | 1.25 |
| Lefty used: whole line | 38 | 177 | 4.27 | 26.90% | 11.80% | 15.10% | 22 | 23 | .686 | 1.29 |
| Lefty used: righty batters only | 38 | 165 | 4.09 | 28.10% | 10.30% | 17.80% | 15 | 23 | .668 | 1.19 |
And here are his starts without lefty pitching by level:
| Level | Starts | IP | ERA | K% | BB% | HR |
|---|---|---|---|---|---|---|
| 2025 Double-A | 2 | 8.2 | 2.08 | 33.30% | 5.60% | 0 |
| 2026 Double-A | 4 | 19 | 6.63 | 24.70% | 9.40% | 5 |
| 2026 Triple-A (after Aug 6) | 7 | 34.2 | 2.86 | 28.90% | 7.70% | 1 |
If his final seven starts of 2026 are any indication, Cijntje could become a major trade win for the Cardinals. After leading the minor leagues in strikeouts in 2026, he may be even better equipped for success in 2027.
The post Why Giving Up Switch-Pitching Could Unlock Jurrangelo Cijntje’s Potential In 2027 appeared first on College Baseball, MLB Draft, Prospects - Baseball America.
