Do not trade away these pitchers... or else!

The early stages of the MLB season tend to be critical for close-up pitching examinations. That's because it's a time where each year's unexpected aces often surface, with 2024 presenting as good an example for us as any.

On this date just one year ago, Garrett Crochet had a 2.00 ERA and a 31.3% strikeout rate through his three starts, on a path to a major breakthrough campaign. Eventual AL Cy Young Award winner Tarik Skubal had a 2.08 ERA and a 32.6% K rate through his two turns. And that's not to say that either's microscopic sample was precisely what mattered, but rather, each had already shown us skills-related signs of what might be to come over the subsequent five-plus months.

This is the dilemma for us in fantasy baseball analysis: We caution not to read too deeply into small sample sizes, yet we must make judgments upon them nevertheless, or risk missing out on league-deciding possibilities. I therefore consider April to be a time to closely scrutinize the starting pitching field, dig deeply into the underlying numbers, and see what's there to hint at the potential emergence of which unexpected sources could become 2025's versions of Crochet or Skubal.

Let's identify five starting pitchers who already appear to be on track to take sizable steps forward this season. Based upon their offseason adjustments, spring training outlooks and/or early season returns, I'm labeling this quintet as my five DO NOT TRADE pitchers.

Spencer Schwellenbach, Atlanta Braves: Here's a pitcher I've written about before, not to mention aggressively targeted in my own leagues. Through two starts, Schwellenbach has looked every bit the part of the fantasy ace. Despite questions about the effects of his 2024 workload spike -- he totaled 168 2/3 IP between the majors and minors, after only 65 in 2023 and zero in 2022 as he recovered from Tommy John surgery -- his stuff hasn't looked any less filthy than it did when he had a 2.47 ERA and a 27.1% K rate across his final 12 starts of 2024.

Schwellenbach already has positive Statcast Run Values on five of his six pitches -- his cutter, just as it was last year, remains his weakest offering. Plus, he's doing a much better job of locating his fastball up and away to left-handed hitters, who have a 42% whiff rate against it thus far (after only 10% in 2024). Yes, he's actually improving, which is exactly what we want to see from a pitcher with whom we might otherwise have had stamina concerns.

The upshot is that, fingers crossed on said stamina holding, Schwellenbach is a legitimate Cy Young Award contender, and a boost beyond the 180-IP threshold would make him a virtual lock for a top-10 positional valuation.

Cristopher Sanchez, Philadelphia Phillies: Another pitcher cited in my preseason "Kings of Command" column, Sanchez has continued to exhibit the heightened sinker velocity that he did during spring training, with the pitch averaging 96.1 mph through two starts (compared to 94.5 mph in 2024 and 92.1 mph in 2023). That boost, and the contrast it provides to his put-away pitches, the changeup and slider, make it all the tougher for opposing hitters to handle them, too.

One of the reasons Sanchez makes this list is the reminder that, despite his 4.09 ERA, he remains one of the year's bigger breakthrough candidates. Bear in mind that his ERA has been adversely impacted by one of his two starts coming against the Los Angeles Dodgers, a game in which Teoscar Hernandez took him deep twice on sinkers. Even with that, Statcast says that Sanchez's expected wOBA on his most-used pitch should be .268, not its current .349, so tuck that away as a matchups-driven aberration.

Sanchez concluded spring training as my No. 36 starting pitcher, but his upside is within the position's top 25, making him a poor choice to trade away (and, naturally, an excellent target if you didn't get him in the draft).

MacKenzie Gore, Washington Nationals: Gore was all the rage in fantasy after striking out 13 Phillies across six shutout innings on Opening Day and his roster rate soared by 10% the following day. However, he was also awfully impressive in his most-recent start against the Dodgers, generating 12 swinging strikes and 19 called strikes among his 100 total pitches. What's changed for Gore this season is a greater reliance upon his secondary pitches, especially when ahead in the count or in put-away mode, which is a big deal for a pitcher who has a curveball (19% career usage) with a 35% whiff rate, a slider (11%) at 37% and a changeup (6%) at 48%.

Gore is now effectively a fastball/slider pitcher against lefties. Other than the three hits (a single, a triple and a home run) he surrendered to Shohei Ohtani on Monday, lefties are just 2-for-15 with 10 K's and a 41% whiff rate against him. That Gore is also doing a better job of getting ahead in the count -- his 64% first-pitch strike rate thus far would represent a career high, coming on the heels of his 65% rate in that category over the final two months of 2024 -- only helps his cause, with all those filthy pitches with which to generate punchouts.

There might not be any pitcher I'm more disappointed to have missed out on this season, as other than Gore's fly ball tendencies (a 24th percentile 39% career ground ball rate) and difficulties minimizing hard contact (a 19th percentile 42% hard-hit rate), little stands in his path to a breakthrough, top-20 SP caliber season.

Casey Mize, Detroit Tigers: The "shot in the dark" pick on this list, Mize's 2025 transformation is far too interesting to peddle him on the fantasy trade market at the probable expected level of return. Yes, he has made only two starts. Yes, he has durability concerns underscored by his having exceeded 110 professional innings in only one of the last five uninterrupted seasons, but the adjustments he has made amplify his upside in a way that most fantasy managers don't yet fully appreciate.

Mize, another of the increasing number of pitchers who went to Driveline during the offseason, has made his splitter -- a staple of his repertoire dating back to his days at Auburn -- more of a focus of his game this season. He's throwing it considerably harder this season, averaging 88.1 mph with the pitch, nearly 2 full mph faster than in any prior year. He has also generated seven strikeouts and 11 swings-and-misses with it (with many of them coming in Monday's start against the vaunted New York Yankees lineup).

This isn't to say that Mize should immediately be treated like a top-40 fantasy starting pitcher. Sure, if that's the caliber of trade package you're being offered for him, by all means cash in now. His ceiling is certainly within that range.

Jesus Luzardo, Philadelphia Phillies: Like Gore, I missed out on many shares of Luzardo. In this case, it was a matter of my being unimpressed by how he looked during the brief spring action in which I saw him. His 9.49 spring ERA probably turned many prospective fantasy managers away. Between that and his injury history -- a pair of IL stints in 2024 and an average of only 21 starts annually from 2022-24 -- he probably won't currently fetch you an appropriate return via trade.

Luzardo has, thus far, shown excellent fastball velocity (96.8 mph, which would be a career high) and is getting oodles of swings-and-misses with both his sweeper and slider (14 total K's, 18 whiffs). It was always apparent during his time in Miami that he had front-of-the-rotation stuff and, considering all the questions surrounding him during the offseason and early stages of spring training, it's promising to see his stuff registering with some of the best rates of any point in his career.

As with Mize, Luzardo is a pitcher worth cashing in on if the offer is generous -- I'd say a top-30 starter's price point should do it -- but I'll point out that he was a pitcher I considered mentioning in my "Phillies dominate the Cy Young balloting" hot take over on our MLB pages. If he somehow could stay healthy for 180 innings -- a bold, bold leap, I know -- he'd have every bit as good a shot at those votes as would the aforementioned Sanchez.