Giants outfielder Mike Yastrzemski is one of baseball’s 10 best players in 2020. At 1.7 Wins Above Replacement (per Baseball Reference), he’s third behind Mookie Betts and Fernando Tatis Jr. among National League hitters.

You say WAR isn’t your thing? No sweat. Yastrzemski is sixth in the NL in OPS and fourth in both OPS+ and OBP. He’s -- wait for it -- eighth in batting average.

So here’s to Giants president of baseball operations Farhan Zaidi and his staff for seeing something in Yastrzemski others apparently didn’t. Yastrzemski's acquisition from the Orioles in March 2019 raised nary an eyebrow.

Here’s also to Yastrzemski for a relentless work ethic and a determination to get better. When the Giants promoted him to the big leagues that May, he took the opportunity and ran with it.

And that’s the thing we most often overlook about Major Leaguers: They’re constantly tinkering with their game, both physically and mentally. They seek help inside their organization and frequently outside it, too.

If they’re open to change -- and many are not -- there are more tools to help them assess their game than ever before. That may be why we’ve seen so many players enjoy such huge jumps in the opening weeks of the 2020 season.

Here are six players who have taken big steps forward that we didn't see coming:

1. Mike Yastrzemski, Giants OF
Key stats: 1.098 OPS, 3 triples, 6 homers

He was a pleasant surprise as a rookie in 2019 (.852 OPS), and now he's a star in 2020. Yastrzemski has established himself among MLB’s most aggressive hitters with two strikes, and he also joined the launch-angle revolution. That the Giants were patient with him had to help, too. He’s better in the Major Leagues than he ever was during seven Minor League seasons.

2. Anthony Santander, Orioles RF
Key stats: 1.056 OPS, 10 doubles, 9 homers

At 25, his named is dotted across the American League leaderboard as the Orioles' patience has paid off. Santander was snatched from the Indians in the 2016 Rule 5 Draft and has developed into an offensive weapon, thanks in large part to an improved strike-zone discipline.

3. Ian Happ, Cubs CF
Key stats: 1.109 OPS, .438 OBP, 6 HR

He was a very good player in 2019 who has played his way into the NL MVP conversation in 2020. Manager David Ross has used Happ in the leadoff spot the last three games, and he reached base seven times in 12 plate appearances.

4. Jesse Winker, Reds DH
Key stats: 1.217 OPS, .493 OBP

Like Happ, Winker already was a good player. What he has become in 2020 is an insanely good player. He’s leading the NL in OPS+ (221) and is lighting up the Statcast leaderboard, scoring in the 97-99th percentile in a variety of categories, including exit velocity (94.1 mph).

5. Dominic Smith, Mets OF/DH/1B
Key stats: 1.156 OPS, .754 slug

Remember him? He was arguably the Mets’ most exciting prospect before Pete Alonso’s 53-homer rookie season last year. Only 25, Smith has found regular playing time by starting games at three different spots and making himself an everyday lineup presence.

6. Robbie Grossman, A’s LF
Key stats: 1.068 OPS, .452 OBP

He’s the outlier on this list because he began the season with more than 2,500 plate appearances. To change his game at this point in his career says plenty about Grossman's willingness to keep searching. After committing to putting the ball in the air more often this year, he has been Oakland’s most productive hitter, with 11 of his first 19 hits going for extra bases.