2:49 PM ET

Trends can change pretty rapidly in this game.

Just two short weeks -- OK, let's say precisely 15 days -- ago, Gleyber Torres was shaping up as one of the season's biggest breakthrough stars, his 48 fantasy points tied for fifth-most among all hitters. It was on that April 11 night, however, that Torres departed in the ninth inning of the New York Yankees' game in Cleveland because of groin discomfort, an injury that cost him merely the start the following night, but has seemingly hampered him both at the plate and on the basepaths ever since. In those 12 following games, Torres has hit just .154 (without an extra-base hit) and an 0-for-2 performance stealing bases, resulting in a mere seven fantasy points.

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It was a swing in performance that fantasy managers, especially those playing in our new standard game, cannot afford to absorb. In just two weeks, Torres' fantasy appeal has taken a significant hit, his roster rate has dropped 5% accordingly, and his trade stock has most certainly declined.

The fact it was an injury-influenced decline makes Torres a somewhat awkward example of the classic "sell-high" player, as on the night of April 11, he sure looked like a player to go get. However, with ESPN's standard leagues moving to smaller rosters this season, it's imperative that we scrutinize recent trends and smaller statistical samples, and trade away hot-starting performers we expect to cool before their value dries up. Had you taken the chance to trade Torres on that date, your fantasy team would probably be better off today -- and it's important that you regularly evaluate whether or not to take that chance.

Ah, and that's the challenge, deciding which hot starters are worth keeping around, and which should be traded away. The last thing any of us wants to do is to spin off a long-range, elite performer, considering how precious his good stats are.

Today's column takes the opposite approach to last week. This time, let's play a game of "sell high or stand by," distinguishing between these two types of hot starters.

Yandy Diaz, 3B/1B, Tampa Bay Rays -- STAND BY: A sabermetric favorite for his annually high Statcast average exit velocity, Diaz has taken his game to an entirely new level this season. His 30% fly ball rate is 10% improved over last season and 11% higher than his career number, his 56% hard-hit rate would easily shatter his previous career best, and his 14.1% Barrel rate is more than double his 6.5% career number. It has taken five seasons into his Rays career to unlock the power potential many suspected he could possess, but even if Diaz regresses somewhat in that department, his plate discipline is so outrageously good -- generally 90th percentile chase and contact rates -- that he's sure to remain a points-league dynamo.

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Cody Bellinger, OF, Chicago Cubs -- SELL HIGH: The seeds are there for some staying power, most notably his 14.1% strikeout and 8.2% swinging-strike rates, which would best his previous lows of 16.4% and 9.5%, set during his 2019 MVP campaign. Bellinger's problem, however, is that none of his elite quality-of-contact metrics from have followed suit in his pursuit of a 2019 redux, and his 31% hard-hit rate and 86.8 mph average exit velocity would be his worst in any single year (yes, beneath even those from his horrendous 2021). He could really go either way with his comeback, but because there is so much torque in his swing, putting him at greater risk of variance than the average player, it's worth to at least shop him around.

Sonny Gray, SP, Minnesota Twins -- STAND BY: The MLB leader in ERA (0.62), Gray has had a lot of things break in his favor -- 93.5% left-on-base rate, a 2.33 differential between his ERA and Statcast expected ERA (2.95), zero home runs despite 27 fly balls allowed -- but he has also shown some awfully promising skills-indicator improvements in the process. Gray is getting positive marks on five different pitches (slider, cutter, curveball, changeup and sinker), and the slider and curveball alone are doing wonders generating swings-and-misses, responsible for 20 of his 34 strikeouts. If you're worried enough about his staying power to peddle him -- something I don't advise considering the return might still be relatively modest -- it should be more about his injury history, as he has exceeded 140 innings only twice in his last six seasons (2020 excluded), than his skill set.

Matt Chapman, 3B, Toronto Blue Jays -- STAND BY: He's the other hitter who, like Diaz, is a "must keep," due to the substantial changes to his offensive game. Take a gander at Chapman's Statcast page, which is a thing of beauty, and for those looking at one for the first time, it's a very, very good thing when a player has bright red dots across each of his first seven in the "2023 MLB Percentile Rankings" group, with four of them reading "100" (for placing in the 100th percentile). Again like Diaz, Chapman has historically delivered elite quality-of-contact metrics, but this season, he has recaptured the degree of in-the-zone contact that was present during his great 2018-19 seasons, while maintaining the extreme fly ball approach he began to show in 2020. Oh, and he's an elite defender, no matter what the first four weeks of metrics tell you, so playing time should be abundant for him.

Brandon Marsh, OF, Philadelphia Phillies -- SELL HIGH: He has been by far the best thing about this year's disappointing Phillies team, but like Bellinger, many of his underlying metrics don't fully support the breakthrough. Sure, Marsh has cut his chase rate by nearly 8%, while boosting his in-zone contact rate by 6%, and it's a good sign that this previously platoon-susceptible hitter has closed his split (a mere 19 points of wOBA) while the Phillies have faced the seventh-largest percentage of their plate appearances as a team coming against lefties. Statcast's metrics deliver some caution, however, as Marsh's expected wOBA (.364) is 125 points beneath his true number (.489), he still hits a lot of ground balls (49% rate) and he's a big risk for K's when in two-strike counts. He's still valued in an OF tier that's largely fungible, so it's worth shopping him around while he's still scorching hot.

Justin Steele, SP, Chicago Cubs -- SELL HIGH: Another "gosh, he's been good" player, and Steele has extended some of the traits that helped fuel his mini-breakthrough in 2022 into this season, offering staying-power hope. His high-spin fastball helps minimize hard contact, and his slider remains a bona fide put-away pitch. Still, Statcast says that Steele's ERA should be closer to three (2.97) than one (1.19), his pitch-specific metrics reflect that his stuff isn't this overpowering, and he's one of the bigger workload-concern arms from his value tier. Steele's 119 innings last season were easily a professional career best -- and this is his 10th year as a pro -- but he is on pace for a robust 223 1/3 frames, which seems awfully unlikely.

David Robertson, RP, New York Mets -- SELL HIGH: He has been excellent as the Mets' de facto closer with Edwin Diaz out for the season, his 53 fantasy points tied for 14th among pure relief pitchers, but that's nothing new for this historically hot-starting pitcher. Robertson has notched at least three saves and scored at least 50 fantasy points (using the new ESPN scoring) in five of the last eight Aprils (2020 naturally excluded), and his career 2.26 ERA and 1.01 WHIP in April are his best in any of the season's six regular-season months. Unfortunately, injuries and later-season fatigue has held him back in recent years, and since the Mets are also using Adam Ottavino to finish games at times, it's a legitimate question whether this closer role is truly Robertson's for the duration -- if even simply today and tomorrow. He's one of the hot-starting closers most worth aggressively shopping.

Jarred Kelenic, OF, Seattle Mariners -- STAND BY: This one is more of a from-the-gut call, because Kelenic's progress this season shares some similar traits to Marsh's. Kelenic's chase rate is down 6% and his in-zone contact rate is up 10% compared to last year, and he has closed what had been a 71-point wOBA split in his first two big-league seasons. Beyond that, Kelenic's improvements look very much different from Marsh's, and if you watch him play, he certainly looks different this year. Kelenic's Statcast page is also full of red, albeit not to the degree that Chapman's is, but it's a refreshing change considering his past struggles. He's doing far better against breaking pitches this year -- .411 wOBA against them, after .210 in 2021 and .101 in 2022 -- and is sporting a 59% hard-hit rate. Kelenic has the prospect pedigree, too, so if you're his manager in any of the 53% of ESPN leagues in which he's now rostered, keep him around and see what develops.