Like anything in baseball, there are always surprises.

The 2021 season brought talk of clear Rookie of the Year favorites, but once the season actually got going, there were more than a fair share of rookie standouts that didn't appear on those early lists.

Consider the top three hottest rookies to start the 2021 season. Yermín Mercedes spent time in the Nationals and Orioles systems, as well as independent ball, before the White Sox made him a Minor League Rule 5 pick in December 2017. Phillip Evans was the No. 19 prospect on the Mets' list all the way back in 2013 and is only now making an impact as a full-time regular with the Pirates. Akil Baddoo underwent Tommy John surgery while in the Twins system in 2019, was a Major League Rule 5 pick last November and has been the story of the season so far for the Tigers. These are early days, but they serve as reminders that prospects of all types are capable of big things when they reach The Show.

These are the 10 hottest rookies of the 2021 season from April 1-12:

1. Yermín Mercedes, DH, White Sox (No. 20)
The story all spring was about how Chicago's AL club would handle its designated-hitter spot in the lineup. Mercedes took hold of the role and hasn't looked back since. The 28-year-old slugger opened the season going 16-for-32 with two homers and three doubles over eight games. His 16 hits, 25 total bases and .556 on-base percentage are all tops among rookies, and he is the only qualified Major Leaguer (regardless of rookie status) hitting .500 or above. With numbers like that, Mercedes -- a catcher in the Minors -- hasn't needed to play any position. He has already provided the White Sox with plenty of value with his bat alone.

2. Phillip Evans, 3B/OF, Pirates (unranked)
The 28-year-old first appeared in the Majors in 2017 but retained his rookie status going into this season due to a limit on his at-bats and days on the roster. Now, Evans is fully ensconced in the Bucs lineup and making the most of his playing time that has only grown since Rookie of the Year favorite Ke'Bryan Hayes went on the injured list with a wrist issue. Evans started out 13-for-32 (.406) with three homers (tied for most among rookies) and two doubles over nine games as of Monday's games -- all while playing third, left, right and even pitcher for a game on April 6. (He retired all three Reds batters he faced.) Only Mercedes has picked up more total bases than Evans' 24 among rookies.

3. Akil Baddoo, OF, Tigers (No. 22)
The only thing holding Baddoo back from a spot in the top two was a lack of consistent playing time in the opening days of the season. It certainly wasn't a lack of impact. A quick review of how the Rule 5 pick began his Major League career. Game one: homer on the first pitch he sees. Game two: grand slam. Game three: walk-off single in the 10th. The left-handed slugger has picked up seven hits in his first 19 at-bats, and five of those have gone for extra bases, including three homers. His 1.000 slugging percentage and 1.381 OPS are both tops among rookie qualifiers. If he didn't have 14 fewer plate appearances than Evans, he would have jumped into the second spot. Still, not a bad way to start for a player who hadn't played above High-A prior to this and was left off the Twins' 40-man roster last autumn.

4. Zach McKinstry, 2B/OF, Dodgers (No. 15)
There always seems to be one Dodgers popup prospect a season, doesn't there? The player to take that early crown this year has been McKinstry, who is making the most of his time in the Los Angeles outfield with Mookie Betts and Cody Bellinger dealing with injury issues. The left-handed slugger has gone 9-for-28 (.321) over nine games. His .679 slugging percentage is tops on the defending World Series champs, while his six extra-base hits (including an inside-the-park home run) rank second, behind only Justin Turner's seven. All of this from a player who hit double-digit home runs only once in his four Minor League seasons prior to 2021. McKinstry isn't just playing like he belongs in the Majors; he's making a case for regular playing time even once Betts and Bellinger are everyday stalwarts again. His defensive flexibility at second base and the outfield should help his case there.

5. Trevor Rogers, LHP, Marlins (graduated from Top 30)
Even when he was posting a 6.11 ERA in his first taste of the Majors last year, Rogers was no stranger to the strikeout, having fanned 39 in 28 innings. His affinity for the K has continued with a rookie-best 16 in 10 innings, and the rest of his numbers have caught up as well, such as a 1.80 ERA and 1.10 WHIP. The 23-year-old southpaw is getting whiff rates above 50 percent on both his mid-90s fastball and low-80s slider, and most recently, those two offerings (along with a changeup) helped him outduel Mets ace Jacob deGrom last Saturday. Rogers won a rotation spot for Miami coming out of Spring Training and doesn't look like a pitcher who will give up that placement anytime soon.

6. Dane Dunning, RHP, Rangers (No. 3, MLB No. 83)
As the prospect the White Sox dealt to acquire Lance Lynn, Dunning is doing plenty to make a strong impression in his first season with Texas. The 26-year-old right-hander has allowed only one earned run over nine innings between two starts again the Blue Jays and Rays. He has fanned 11 and walked only two in that span. With four above-average pitches and good control, the University of Florida product has the arsenal to fit comfortably into the Rangers' Major League rotation right now, and these early results could point to him taking an even larger role as a top starter for the club as the season wears on.

7. Jazz Chisholm Jr., 2B/SS, Marlins (No. 4/MLB No. 58)
Since winning the second-base job out of the spring, Chisholm has solidified his place as one of the most exciting players on the Marlins roster and even the Majors at large. He proved that by taking a 100.4 mph pitch from deGrom deep into the Citi Field upper deck over the weekend. His plus speed also came into play when he stole second (despite a pickoff attempt from Rays lefty Rich Hill) and third on successive plays on April 3. In fact, those two thefts make Chisholm the only rookie with multiple steals at this stage of the early season. His .888 OPS -- aided by six walks in 30 plate appearances -- also places fifth among qualified rookies. (That comes despite just a .217 average.) His combination of pop, speed and middle-infield play could make Chisholm a South Beach sensation for years to come.

8. Casey Mize, RHP, Tigers (graduated from Top 100)
The 2018 top overall pick admittedly struggled during his first taste of the Majors in last year's abbreviated campaign. It's been a different tale in the Motor City this time around. Mize tossed seven scoreless innings against the Astros on Monday, thus completing his best start in The Show thus far. His 0.82 ERA through two outings is lowest among all rookie starting pitchers on the young season, and he has matched that with nine punchouts in 11 total frames. Mize has upped the usage of both his fastball and splitter in his early starts of 2021, and it's worth following how much he continues with those trends given the promising results.

9. Michael Kopech, RHP, White Sox (No. 2, MLB No. 34)
Could Kopech be this year's version of Devin Williams? The 24-year-old right-hander is certainly pitching like a reliever capable of winning a Rookie of the Year Award. Kopech is averaging 97 mph on his fastball and getting a whiff rate of 41.9 percent on that pitch alone, but the slider -- with its 70 percent whiff rate -- might be the better offering right now. In fact, seven of his 11 K's over 6 1/3 innings have come on the slider. Kopech has yet to allow an earned run in three appearances and has surrendered only one single and two walks to the 22 batters he has faced. He has the stuff to be an effective starter, but if he continues to dominate out of the bullpen, the White Sox might decide to keep him where he can be truly elite.

10. Randy Arozarena, OF, Rays (graduated from Top 100)
He's back! OK, not "10 homers in 20 postseason games" level of back, but last year's playoff hero is performing solidly enough to prove his 2020 self wasn't a flash in the pan. Arozarena has opened 11-for-38 (.289) with two homers, a double and five RBIs. He also began the campaign on an eight-game hitting streak and has reached base safely in all nine of his 2021 contests. On top of the bat, Arozarena has flashed some good leather in right field for the Rays, including when he made a catch-of-the-year candidate on April 5 at Fenway Park. The preseason AL Rookie of the Year favorite is using every tool in his kit to stay in that race through the early going.