One of the most important skills to have as a fantasy baseball manager early in the season is to understand small-sample size variance and not overreact. That’s especially true in the first month of the season, as you don’t want to throw away years of data based on a new 30-day sample. However, as we’re now a week into May, it slowly becomes more difficult to ignore the elite performances of newcomers when you have a struggling veteran in your lineup. While sometimes it’s worth it to pull the trigger on the apparent up-and-coming breakout, you’ll still want to be wary of potential regression.
In this piece, we’ll take a look at three players who have looked like fantasy superstars so far, at least on the surface. We’ll discuss two hitters who are having career years, along with a pitcher who has been nearly unhittable all season. The big question, though, is whether they are legit. In other words, will they continue to be mainstays in your lineup, or will they end up back on the waiver wire where they started before you know it?
Mickey Moniak, OF, COL
Mickey Moniak has been on fire over the past couple of weeks, batting .404 with five home runs in the past 14 days. On the season, he’s slashing a robust .333/.378/.745 with 19 runs, 11 homers, and 21 RBI. While this level of production is clearly unsustainable, as I doubt anyone considers Moniak a superstar, his 92nd percentile xSLG of .536 does show that he’s earning these great results. Even last season, his xSLG finished in the top 10 percent of the league, as he slashed .270/.306/.518 with 24 homers in 135 games. This is clearly more than just one hot month, and the 27-year-old is a former number one overall pick, after all. Is he finally delivering on those expectations?
An important thing to note is that this long-awaited emergence conveniently came as soon as he went to the Rockies. If you take a look at Moniak’s splits, it’s clear that he loves Coors Field.
Those numbers on the road are what we were used to seeing from the youngster pre-Rockies, and it was no different in 2025 when he slashed .230/.255/.425 on the road while batting over .300 at home. The other major negative for his fantasy value is that he rarely plays against lefties, as he hit only .222 against them last year, and .111 so far this year.
Verdict: Slightly legit. I went with slightly legit instead of not legit, just for the fact that I do think he is worth starting against righties at home. The only problem is that it makes him extremely hard to roster in weekly lineup leagues, and even in shallower daily leagues, it’s tough to devote a roster spot to someone who will be bad in the 50% of the games he plays on the road, along with not even starting whenever a lefty is on the mound. He’s sure to regress from this current crazy pace, but he’ll still be a viable streaming option on homestands.
Ildemaro Vargas, 1B/2B, ARI
Ildemaro Vargas was taking 2026 by storm, beginning the year with a 24-game hitting streak that finally came to an end on Saturday. On the season, he’s slashing .382/.406/.657 with 19 runs, six home runs, and 21 RBI as one of the biggest surprises of the year. He’s done so by taking an Arraez-esque approach, posting a 39.3% squared up rate (99th percentile) and a 10.2% strikeout rate (97th percentile), despite a suboptimal 5.4% barrel rate and 38.0% hard-hit rate.
However, Vargas is 34 years old and has always posted an elite squared up rate and strikeout rate, and the most he’s gotten out of it up until now is a .270 batting average in 38 games last season. So what changed? His ground ball rate has decreased from 58.8% last season to 45.7% this year, with his pull air rate skyrocketing from 11.8% to 23.9%. This definitely explains the increase in home runs, as pull-air rate can counteract some suboptimal exit velocities.
Verdict: Not legit. It’s yet to be seen if his new launch angles will stick throughout the season, but either way, some serious regression is coming. While his 23.9% pull air rate is good, it’s not nearly on the same level as someone like Isaac Paredes, who offsets his poor exit velocities with a pull air rate that consistently nears 40%. Additionally, the .382 batting average is obviously unsustainable, and even if he keeps up the great contact metrics, a .300 average would likely be closer to the best-case scenario. Once you bake in that regression to both power and average, you’re left with someone who probably isn’t worth rostering in standard-sized leagues.
Davis Martin, SP, CHW
Davis Martin was already enjoying a great season heading into his start on Monday night, where he pitched an absolute gem against the Angels. He tossed seven shutout innings, allowing five hits and striking out 10. The 29-year-old induced 19 whiffs on the night, with a whopping 82% whiff rate and 69% CSW coming on his slider, which he threw 13 times (15%). That pitch in particular has been dominant all season long with a 59.6% whiff rate and .119 xwOBA.
Martin has yet to allow more than three runs in a start through seven outings this year, with five of his seven appearances being one run or less. He now owns a sparkling 1.64 ERA and 1.02 WHIP to go along with 43 strikeouts and eight walks in 44 innings. The biggest difference in his approach this season compared to 2025 is the use of his cutter, which has increased from 1.8% usage last season to 16.6% this year. While he has made a noticeable change that is seemingly leading to a breakout, the quality of contact metrics don’t quite back that up. He’s allowed a 90.9 mph average exit velocity (20th percentile) and 45.7% hard-hit rate (21st percentile), which has led to an equally bad .274 xBA. Those metrics suggest some good luck is coming into play, although his 25.5% strikeout rate and 4.7% walk rate are both very promising signs.
Verdict: Somewhat legit. I think there’s clearly some luck involved here, as he’s still allowing tons of hard contact and the slider is getting whiffs at a completely unsustainable rate. So if you’re hoping that Martin is breaking out as an ace, I don’t believe it. However, once the regression hits, that doesn’t necessarily mean he’ll be back to waiver-wire fodder that everyone forgets about. While none of his pitches grade out great in terms of stuff, a diverse six-pitch arsenal can easily be more effective than the individual pitch metrics would suggest. The increased use of his cutter could have unlocked the extra effectiveness of his slider, and I do believe he will stay fantasy relevant in standard-sized leagues all season long as a mid-to-late range rotation option, which is still a nice bump for someone who was an afterthought in most drafts this pre-season.
