Each week in this report, I’ll be monitoring the performances of MLB rookies. I will emphasize those rookies who put up especially positive performances, while also taking care to mention rookies who are underperforming expectations. In both cases, I will dig into the underlying stats and attempt the difficult task of projecting forward.

Rookies are typically more unpredictable than their more experienced colleagues, and can, therefore, be a source of great profit in fantasy baseball; or great frustration. Stay tuned to this space every week to find out which newbies should be in the mix for your squad. So far I have avoided repeating any players, so check out last week’s Rookie Report to keep up to date on all the hottest youngsters. As I have begun to exhaust all the interesting rookies, starting this week, I will be revisiting some of the more impactful performers.

All stats are current prior to Tuesday’s games, and, as noted last week, any quoted Statcast numbers are directly from Baseball Savant.

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Swimming

Cody Bellinger (1B/OF – LAD)

Following the placement of Joc Pederson on the 10-day DL, top prospect Cody Bellinger was called-up from Triple-A to make his MLB debut. In seven games Bellinger has given the league a glimpse of his future upside, slashing .320/.393/.600 with two homers, a 96.5 mph average exit velocity on line drives and fly balls, and a fine 10.2% Barrels/PA rate. Strong walk rates have been a staple of Bellinger’s minor league career, while his strikeout rate has bounced between 16% and 28%. Average was never expected to be Bellinger’s carrying tool, but as usual, if he can control his strikeout rate in the majors, he may be able to maintain a decent average while clobbering homers. In the short term, Bellinger appears destined to be optioned back to Triple-A when Pederson returns at the end of this week. Given Adrian Gonzalez’s age, Yasiel Puig’s injury history, and the Dodgers’ comfort with Enrique Hernandez and Scott Van Slyke in complementary roles, owners who grabbed Cody should try to hold him. As long as the expectation for his batting average is not much higher than .250, Cody Bellinger could easily be valuable contributing 20 HR in a half-season.

Guillermo Heredia (OF – SEA)

I invoked Heredia’s name in last week’s Report when discussing Taylor Motter’s playing time prospects. With the return of Jean Segura from the DL, it now appears that Heredia is seeing near-everyday playing time in left field. He also has two appearances in center. A relative unknown out of Cuba in 2016, the 26-year-old Heredia moved quickly through the minor leagues, displaying excellent contact ability, but limited power and speed at every level. So far in the majors between 2016 and 2017, Heredia has posted an excellent 87.3% contact rate with 9.4% BB% and 12.6% K%. Contact and average are about the extent of Heredia’s expected production going forward; his three HR and one SB in 159 plate appearances so far are not particularly exciting. Heredia seems to be a high-variance fantasy commodity. Odds are that his low-power, high-contact, defense-first skill set does not distinguish him much in Seattle’s outfield when Mitch Haniger returns and he finds himself on the bench, but there is also a non-zero chance that Heredia has been overlooked as an older prospect from Cuba and develops quickly into a solid everyday player. This makes him in interesting play in deeper leagues, where his contact ability will limit his downside while owners wait and see.

Jose Leclerc (RP – TEX)

The fireballing righty reliever debuted last year, and continued a trend of poor walk rates from the minor leagues. In 15 innings, he pitched to a 1.80 ERA despite a 1.60 WHIP. So far this year, Leclerc has seemingly found his control and has amped up his SwStk% to an eye-popping 23%, all of which has resulted in a 14.4 K/9 and 0.90 BB/9 and a 0.90 ERA. He currently leads all rookie pitchers in FanGraphs WAR. Mysterious unavailability on Monday aside, Leclerc is in the middle of an unsettled Rangers bullpen that has already spit out Sam Dyson, last year’s usurping closer. For the moment, Matt Bush has control of the ninth inning, and Jeremy Jeffress is the consensus setup man. Beyond that, Keone Kela and Tony Barnette are also in the mix for high-leverage situations, so Leclerc does not have a clear path to a late-inning setup role, let alone a shot to close. Also of concern is that his Zone% (rate of pitches thrown in the strike zone) is largely unchanged from last year at 44.2%. On the positive side, his first strike rate is up to 70.3% from 57.6% last year, and he is generating more swings and less contact out of the zone as well as less contact on swings in the zone. Those in holds leagues should give Leclerc a look, keeping a close eye on his walk rate and his usage by the Rangers.

Sinking

Christian Arroyo (3B/SS – SF)

Considered one of the Giants’ top prospects coming into the season, Arroyo had a down year at Double-A Richmond 2016 with only three HR and a .274 average, but is still considered by some prospect analysts to have a well above average hit tool. His spot in the majors was opened by the injury to Brandon Crawford, but he has been playing primarily at third, also making three appearances at shortstop. With Crawford expected back this weekend, Arroyo’s playing time is questionable going forward, depending on how indispensable the organization views Eduardo Nunez. At the plate, Arroyo has surprisingly launched two home runs, albeit with a .250 AVG. His 27.3% K% is surprisingly high, but in only 33 plate appearances, his solid 83.6% contact rate is more trustworthy. Still, without a carrying power or speed tool and playing time questions, Arroyo is best left on the waiver wire in all but the deepest leagues.

Jharel Cotton (SP – OAK)

When last we visited Cotton in the first Rookie Report, he had put together two starts with mixed results, but nothing seemed alarming enough to move me from my optimistic preseason position. Since, Cotton has not righted the ship, giving up five, two, and six (three earned) runs. His 6.33 K/9 and 4.00 BB/9 are both poor, and his SwStk% has plummeted to 8.4% from 12.5% last year. Looking deeper, it seems batters are swinging less frequently on his pitches out of the zone are making contact more often when they do. A quick look at Brooks Baseball does not reveal much difference in Cotton’s pitch movement, so it may be that batters have simply made an adjustment to him given a larger major league sample from which to draw. Cotton’s status as an undersized fringe prospect would not ordinarily afford him much margin for error. Oakland lacks a lot of high-end pitching talent, and with Sean Manaea and Daniel Mengden on the DL, Cotton is not likely in jeopardy of losing his rotation spot. In mixed redraft leagues, Cotton can likely be dropped, but there is still enough track record to hang on in keeper leagues. For sure, he deserves to be on fantasy benches until he shows that he can successfully adjust back to the league.

Hunter Renfroe and Manuel Margot (OF – SD)

Also in the first Rookie Report, I preached some degree of cautious optimism on both Renfroe and Margot, Margot especially impressing with his early power output. Margot has stayed pegged at three HR, while Renfroe has hit three more homers, but seen his average drift down to .210. As expected, neither is walking much, but Renfroe is striking out at a somewhat concerning 26.9% clip. After being caught stealing three times in a row, Margot has contributed three successful swipes in the last week. For a pair of prospects this free-swinging, there are likely to be many highs and lows as the season progresses. Near 20 homers for Renfroe and near 20 steals for Margot still seem reasonable, neither with a particularly helpful batting average. If that was good enough for fantasy owners pre-season, it should still be good enough now.



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Andrew Dominijanni is a correspondent at FantasyPros. For more from Andrew, check out his archive and follow him @ADominijanni.