How long can baseball's surprising statistical leaders keep it up?

Kole Calhoun did not have a good 2018 season. He hit .208 with 19 home runs, and his wOBA of .294 ranked 178th out of 194 qualifiers. For one month, however, he was as good as any hitter in the game. He hit .322 in July with 10 home runs and 25 RBIs and had the fourth-highest OPS. Only Matt Carpenter had more home runs that month, and only Khris Davis had more RBIs.

Jonathan Schoop did not have a good 2018 season. He hit .233/.266/.416 with 21 home runs. But in July, he hit .360 with nine home runs.

Joc Pederson was better than Calhoun and Schoop, hitting .248/.321/.522 with 25 home runs in a platoon role. In June, he hit 10 home runs and slugged .867 in just 67 plate appearances.

Surely you remember Didi Gregorius' April. He hit .327/.421/.735 with 10 home runs and 30 RBIs. He finished with 25 home runs and 87 RBIs, so more than a third of his production came in those first 28 games.

We can do with this with pitchers as well. Daniel Mengden went 4-1 with a 1.51 ERA in May. Sean Newcomb went 5-0 with a 1.54 ERA that month. Jake Arrieta beat both with a 0.90 ERA. Carlos Rodon finished 6-8 with a 4.18 ERA, but he went 5-0 with a 1.84 ERA in nine starts in July and August.

You get the idea. Players of all abilities can have huge months -- not just the superstars. But we notice the big months more when they happen in April because we see the names at the top of the stat leaderboards. It's a reminder of what makes the game so magical: Mike Trout is Mike Trout because he does it month after month, but for one month, Kole Calhoun was Mike Trout. The line between one of the greatest players of all time and a veteran having a bad season is much smaller than we sometimes realize.

With that in mind, let's look at some of the early leaderboard surprises and decide if they can possibly keep it up.

Tim Anderson, White Sox: .365 average (first in AL)

Anderson hit .240 last season, and the surprising aspect of his start is that his chase rate has climbed 4 percent from 2018, when he was one of the biggest free-swingers in the game. It defies logic that an even more aggressive approach has worked, but his underlying metrics are trending positively compared to last season: His exit velocity is up, his hard-hit rate is up from 27.9 percent to 36 percent, and his swing-and-miss rate is down. There has been some good fortune -- his expected batting average heading into Wednesday was .315 -- but in general, his quality of contact has been very good.

Still, he's riding a .413 BABIP and has drawn only two walks. Javier Baez has succeeded with this extreme approach, but Baez has freakish bat speed and raw power. Even if Anderson sustains some of his hard-hit improvement, I think the high chase rate will haunt him, and he will fall under .300 by season's end.

Jeff McNeil, Mets: .365 average (second in NL)

To think the Mets spent the offseason trying to find ways to not play McNeil after trading for Robinson Cano and signing Jed Lowrie, but injuries to Lowrie and Todd Frazier opened up regular playing time for McNeil, and he's not about to lose it now.

He's what we might call a throwback player, given the current devotion among hitters to home runs. McNeil focuses on putting the ball in play instead of launching it in the air and has a strikeout rate under 10 percent. While he has just one home run, don't be fooled into thinking he's a soft-contact guy. His average exit velocity of 90.7 mph is the same as that of hitters such asXander Bogaerts and Manny Machado. His expected batting average is .325, so he's hitting line drives and hard grounders. I would predict a .300 average, and given his doubles plus some walks, that's an effective hitter -- and a nice change of style in today's all-or-nothing game.

Trey Mancini, Orioles: .342 average (fourth in AL)

Mancini is hitting for both average and power (17 extra-base hits) after hitting .242 with 24 home runs last year. Where has that 100-point increase in batting average come from? In his case, it looks like it's all about launch angle:

He isn't hitting the ball harder, but he's hitting at more favorable angles. His ground ball rate has declined from 55.5 percent to 36.8 percent. That means more line drives and a higher BABIP. Mancini is not going to hit .342, but if he keeps the strikeout rate at 22 percent or below, he could be a legit .300 hitter.

Eddie Rosario, Twins: 11 home runs (tied for AL lead)

Like McNeil and Mancini, Rosario is 27. Is the age-27 peak season still a thing? Rosario has always had elite bat speed and hit 51 home runs the past two seasons, so it's not as if this power surge is out of nowhere. He also hit four of his 11 home runs last weekend in Baltimore. Some of Rosario's numbers are up: exit velocity and what Statcast calls "barrel rate" (a hard-hit ball at the optimal launch angle). He remains an aggressive swinger, and six games against the pitiful Orioles pitching staff certainly helped.

Rosario also has always been a streaky hitter. He hit .350 with 15 home runs in May and June last year, then hit .259 with four home runs in July and August. He hit 16 home runs in August and September 2017. I can see Rosario topping 30 home runs for the first time, but I'm not convinced that he has the consistency to get to 40.

Domingo Santana, Mariners: 30 RBIs (tied for AL lead)

Santana's overall batting line isn't anything special -- .284/.349/.470, six home runs -- and he strikes out a lot, so you might guess that he has been clutch with runners on base. He has! He's hitting .417 with runners in scoring position. To his credit, his overall strikeout rate is 26 percent, but it's just 9.5 percent with RISP, so he appears to be making a concerted effort to cut down on his swing in those situations.

Two players hit .400 with RISP last season -- Joe Mauer (.407) and Yuri Gurriel (.403) -- so maybe Santana can do this all season. And, yes, he could drive in 100 runs while slugging under .500. It happens all the time. Heck, Albert Pujols drove in 101 runs in 2017 while slugging .396 (thanks, Mike). Still, would you predict Santana to lead the AL in RBIs at season's end? No. We all know that will be Luke Voit.

Tyler Glasnow, Rays: 5-0, 1.75 ERA (tied for AL lead in wins, leads in ERA)

Glasnow was a popular breakout candidate heading into the season after he pitched pretty well with Tampa Bay down the stretch after the trade with the Pirates, but I wasn't so sure about that. He had a 4.20 ERA with the Rays and did start throwing more strikes, but he also allowed 10 home runs in 55 innings and averaged just five innings per start.

Well, he's breaking out in a big way, and he's doing it basically with two pitches: an upper-90s fastball and a knee-breaking curveball. (He'll mix in a few changeups and sliders.) He has always had the big stuff but always made a mess of things with his inability to throw enough strikes. But now:

2018: 127th out of 140 pitchers in strike rate (minimum 100 IP)

2019: 18th out of 125 pitchers in strike rate (minimum 25 IP)

It's amazing what throwing strikes will do. I guess there's a chance the mechanics slip backward or something, but he looks like a Cy Young candidate.

Marco Gonzales, Mariners: 5-1, 3.28 ERA (tied for AL lead in wins)

The Gonzales bubble burst a little bit on Wednesday, as he had his first bad start and got knocked out in the second inning. Still, his ERA is a solid 3.28, and he has allowed just four home runs in 46 innings. He might be even better if not for Seattle's league-worst defense, as his .313 BABIP against is a little high. His expected batting average allowed via Statcast data is .244; in reality, it's .273.

His cutter induces some soft contact, which helps make up for a mediocre strikeout rate, and he's pitch-efficient, which helps him go deeper into games without getting to 100 pitches. Wins, of course, are somewhat team-dependent, and as the Mariners' offense cools down, he's going to find those wins harder to come by. I think he'll beat last year's 4.00 ERA, even with that atrocious defense, but he is not going to beat last year's 13 wins.

Kirby Yates, Padres: 14 saves (leads NL)

Yates was dominant last season, and he's off to a great start, with one run in 16 innings (with 25 strikeouts). Here's all the evidence you need: While poking around some of the Statcast data, I saw that he has the third-lowest expected wOBA based on quality of contact. He doesn't light up the radar gun (93-94), but the fastball/splitter combo has worked in the past for pitchers who didn't throw 93 (think Koji Uehara). He's good.