Following up my MVP's and Cy Young's, below is how I would vote for the Rookie of the Year and Reliever of the Year and why. I will not be picking a Manager of the Year because I don't believe I'm qualified given that I haven't been around these men.
AL Rookie of the Year: OF Kyle Lewis, Seattle Mariners
Stat line: 11 HR, .262/.364/.437, 5 SB, 126 wRC+, 1.7 fWAR in 58 games.
After white-hot starts from Kyle Lewis and Luis Robert, we didn't end up with any true standouts in this race, and there are a lot of players jumbled right at the top for me. Personally, I lean Lewis here, but I would not argue Cristian Javier and you could make a compelling case for Robert, Shaun Murphy, or even James Karinchak. I chose Lewis for a couple of reasons, not the least of which is the size of his body of work. He led all American League rookies with 242 plate appearances and tied for the lead with 58 games played, and looked good doing it. His eleven home runs also tied for the lead and his 1.7 fWAR finished first, on pace for nearly five in a full season. I was particularly impressed by his willingness to take a walk, and his 34 led all AL rookies by a wide margin over second place Yoshi Tsutsugo's 26. Lewis was also a solid defender in the Seattle outfield and stole five bases to boot, truly contributing in every facet for the Mariners.
Runner-up: RHP Cristian Javier, Houston Astros
Stat line: 5-2, 3.48 ERA, 0.99 WHIP, 54/18 KBB in 54.1 IP.
I was a big fan of what Cristian Javier pulled off this year as a 23 year old, leading all AL rookies (min. 35 innings) in ERA (3.48) and WHIP (1.00) in a year where the baseballs were flying farther off of bats than they ever have. Javier allowed just 36 hits in 54.1 innings, and with the exception of one rough start against the AL West champion A's, he allowed no more than three runs in eleven of his twelve appearances. He also went at least five innings in seven of his ten starts, which might not sound particularly impressive, but in 2020 managers had very, very short leashes for their young pitchers and Javier managed to extend his. As far as leaderboards go, beyond ERA and WHIP, he was third in strikeouts (54) and fourth in innings (54.1), though he also led in home runs allowed (11).
Honorable mention: C Sean Murphy, Oakland Athletics
Stat line: 7 HR, .233/.364/.457, 0 SB, 131 wRC+, 1.5 fWAR in 43 games.
Sean Murphy may have only appeared in 43 games, less than three quarters of the season, but he made a big impact. It's very, very hard nowadays to find good catching, and Murphy's 1.5 fWAR put him fourth among all AL catchers, rookie or not rookie. He blasted seven home runs (a 19 HR pace) and got on base at a .364 clip despite playing at a pitcher-friendly home park, and he held his own with strong defense behind the dish. He caught fire in September and slashed .277/.424/.638 with five home runs over his final 16 games, really helping the A's compensate for the loss of Matt Chapman. Overall though, it goes back to the second sentence of this paragraph: it's very hard to find Good Catching and Sean Murphy was a Good Catcher.
Others: OF Luis Robert (CWS, 1.5 fWAR), SS Willi Castro (DET, 1.3 fWAR), RHP James Karinchak (CLE, 2.67 ERA), LHP Justus Sheffield (SEA, 3.58 ERA), RHP Brady Singer (KC, 4.06 ERA).
NL Rookie of the Year: RHP Devin Williams, Milwaukee Brewers
Stat line: 0.33 ERA, 0.63 WHIP, 12.63 RE24, 53/9 K/BB in 27 IP.
I'm not a big fan of giving awards such as the Cy Young and Rookie of the Year to relievers, but come on, you can't pitch much better than Williams did this year. A 0.33 ERA, just eight hits and nine walks in 27 innings, and a ridiculous 53 strikeouts in 100 plate appearances are just unreal. His 12.63 RE24, which I think is a pretty good stat with which to measure relievers, led all MLB relievers, AL or NL and rookie or not rookie. He allowed three unearned runs against one earned run, but even if you add those three into his RA9, it still sits at a clean 1.33. After a tough second outing of the year in Pittsburgh, he finished it off with 24.2 shutout innings (one unearned run), a 0.53 WHIP, and a 49/7 strikeout to walk ratio over his final 20 appearances. That changeup, man. It's untouchable.
Runner-up: RHP Tony Gonsolin, Los Angeles Dodgers
Stat line: 2-2, 2.31 ERA, 0.84 WHIP, 46/7 K/BB in 46.2 IP.
Tony Gonsolin may have only pitched 46.2 innings and won only two games, but I don't think he could have pitched much better than he did when he was on the mound. He allowed just 32 hits, and perhaps more impressively, only seven walks in those 46.2 innings for a ridiculous 0.84 WHIP, and his 2.31 ERA was second among NL rookies (min. 35 innings). In his nine appearances, he allowed zero or one earned runs six times, and he only walked multiple batters in an outing once. He didn't allow a run over his first three starts and saw only eight baserunners in those 14.2 innings, and on September 20th, he struck out ten in a very impressive start at Coors Field. In a year where baseballs were absolutely flying, everything he did becomes all the more impressive.
Honorable mention: 3B Alec Bohm, Philadelphia Phillies
Stat line: 4 HR, .338/.400/.481, 1 SB, 138 wRC+, 1.2 fWAR in 44 games.
Alec Bohm, like Gonsolin, didn't play the whole season, appearing in just under three quarters of his team's games. However, it's hard to argue with a .338/.400/.481 slash line just two years after he was drafted out of Wichita State. Bohm led National League rookies in hits (54) and RBI (23), and when you set the minimum at 100 plate appearances, he led in all three slash categories as well. He wasn't a superstar at third base but he held his own at a tough position, and overall there wasn't a greater sum of offensive production among any NL rookies. Jake Cronenworth may have played ten mores games with a strong season of his own, but he only had twelve more plate appearances and I don't think that's enough to make up for the gap in production.
Others: 2B Jake Cronenworth (SD, 1.4 fWAR), RHP Dustin May (LAD, 2.57 ERA), 3B Ke'Bryan Hayes (PIT, 1.7 fWAR), LHP Kwang Hyun Kim (STL, 1.62 ERA), RHP Ian Anderson (ATL, 1.95 ERA).
AL Reliever of the Year: RHP Liam Hendriks, Oakland A's
Stat line: 1.78 ERA, 0.67 WHIP, 8.17 RE24, 37/3 K/BB in 25.1 IP.
Liam Hendriks was my 2019 AL Reliever of the Year when he put up a 1.80 ERA and a 124/21 strikeout to walk ratio over 85 innings, and he will repeat again in 2020. When you combine in 2020's 1.78 ERA and 37/3 strikeout to walk ratio this year, he has a 1.79 ERA, a 0.90 WHIP, and a 161/24 strikeout to walk ratio over 110.1 innings since the start of last year. In addition to walking just three batters (one intentionally) this whole season, he also allowed just 14 hits in 25.1 innings, so Hendriks very rarely even had to pitch out of the stretch. Combine Hendriks with Jake Diekman (0.42 ERA, 31/12 K/BB) and JB Wendelken (1.80 ERA, 31/11 K/BB), and you can see why the A's did so well this year. I don't think this 2020 season quite matches what he did in 2019, but from just 2019-2020, Liam Hendriks has been the best relief pitcher in baseball.
Runner-Up: RHP Tyler Duffey, Minnesota Twins
Stat line: 1.88 ERA, 0.79 WHIP, 8.38 RE24, 31/6 K/BB in 24 IP.
Tyler Duffey barely hung on the Twins' roster from 2016-2018, but was very strong with a 2.50 ERA and an 82/14 strikeout to walk ratio in 2019, then took it to another level with a 1.88 ERA, a 0.79 WHIP, and a 31/6 strikeout to walk ratio in 24 innings in 2020. Those 24 innings saw him allow just 13 hits and six walks, so just like Hendriks, he was very rarely even in trouble on the mound. There's no single area where Duffey was particularly exceptional, but he was very strong by every measure and the end result was one of the best seasons we saw out of an AL reliever this year.
Others: RHP Codi Heuer (CWS, 1.52 ERA), RHP Nick Anderson (TB, 0.55 ERA), RHP Jesse Hahn (KC, 0.52 ERA).
NL Reliever of the Year: RHP Devin Williams, Milwaukee Brewers
Stat line: 0.33 ERA, 0.63 WHIP, 12.63 RE24, 53/9 K/BB in 27 IP.
See his rookie section. Devin Williams was untouchable. Nobody is even remotely close to him here.
Runner-up: RHP Chris Martin, Atlanta Braves
Stat line: 1.00 ERA, 0.61 WHIP, 6.72 RE24, 20/3 K/BB in 18 IP.
There really weren't any standouts behind Williams, so with all of 18 innings pitched to his name, Chris Martin was the second best reliever in the National League last year. In those 18 innings, he allowed just eight hits, three walks (one intentional), and one hit batsman for a ridiculous 0.61 WHIP that bested even Williams. He struck out 20 of the 66 batters he faced (30%) and only allowed multiple baserunners in two of his 19 appearances. In the other 17, it was zero or one baserunners for his opponents.
Others: LHP Adam Kolarek (LAD, 0.95 ERA), LHP Drew Pomeranz (SD, 1.45 ERA), RHP Edwin Diaz (NYM, 1.75 ERA).