That the 2024 MLB season has been full of surprises isn't actually surprising. It's baseball. As much as everyone pretends to think they do, nobody ever knows what will happen.

But since not all surprises are created equal, let's dive into 10 storylines that nobody could have seen coming.

We're talking about players, teams and indeed entire divisions that were supposed to go one way after Opening Day, but have instead gone in other directions. Some are good. Some are not so good.

What we're not talking about, mind you, is injuries. Such things are inherently unpredictable. And besides, we'd be here all day if we took the time to talk about all the pitching injuries that have already happened this year.

Let's start with five player-specific developments and expand our horizons from there.

Jackson Holliday Fought The Show and The Show Won

Remember the reaction when the Baltimore Orioles reassigned Jackson Holliday to minor league camp toward the end of spring training?

Nobody captured the general sentiment better than Holliday's father, Matt, who told a St. Louis radio station: "I think it's always disappointing when you think you've done something that you've earned and it doesn't go your way."

His gripe was a real one. Far from "just" the No. 1 prospect in MLB, the 20-year-old Holliday had posted a .941 OPS in the minors in 2023 and was sitting on a .954 OPS in Grapefruit League play. Yet the Orioles didn't think he was ready for The Show? Come on.

Looking back now, though, they were more right than even they knew.

The excitement that accompanied Holliday's arrival on April 10 not only didn't last long, but was completely shattered as he went just 2-for-34 with 18 strikeouts in 10 games before he was sent back down on April 26. Notably, his 59.4 whiff percentage against fastballs is still the highest such mark among qualified hitters.

Will Holliday be a hit in the majors eventually? Yeah, probably. But his initial failure to become one should serve as a reminder that, even for supposed prodigies, hitting major league pitching is a very, very hard thing to do.

Corbin Carroll Doesn't Look Right At All

As for a young hitter who did take to the majors immediately, let's pause for a moment of appreciation for how Corbin Carroll introduced himself to MLB fans.

In a span of roughly 15 months across 2022 and 2023, he:

• Posted an .862 OPS with 29 home runs and 56 stolen bases in 187 games
• Signed an eight-year, $111 million contract extension
• Helped guide the Arizona Diamondbacks to the 2023 World Series
• Won the 2023 National League Rookie of the Year

Not bad! And since 2024 would only be Carroll's age-23 season, everyone had every reason to suspect that his star power had only just begun to take off.

Instead, he's batting .203 with only one home run through 33 games.

There are forgivable slumps, and then there are truly alarming slumps. This one is a case of the latter. Carroll is dealing with substantial drop-offs to both his contact quality and his trademark speed, for which his average sprint is down 1.2 feet per second.

Carroll is achieving his goal of cutting down on strikeouts, but not so much that it's worth the sudden flaws in his game. Hopefully, him recognizing that and adjusting accordingly will be what wakes him from this nightmare.

Ronald Acuña Jr., Now with Less Power

Elsewhere on the topic of guys who had sensational seasons in 2023, let's grant that it would have been hard for Ronald Acuña Jr. to have an even better year in 2024.

The 41 home runs and 73 stolen bases got the most headlines, but Acuña also led MLB with 217 hits, 149 runs scored, 283 total bases and with a .416 on-base percentage. It was...a lot...of good stuff.

But even if he was unlikely to follow it up with something better, anyone could have expected more than, well, this.

It's all well and good that the 26-year-old is 14-of-15 stealing bases, but he's hit only two home runs and lost 234 points off his 2023 slugging percentage.

Just as alarming is what's underneath the hood. Acuña already has more multi-strikeout games this season than he did all of last season, and none of his contact quality metrics are up to par either.

Because Acuña missed time during spring training because of a knee injury, one can't help but wonder if he's either playing hurt or simply out of whack. Atlanta had better hope it's the latter, as it's going to take a village to keep covering up Spencer Strider's absence.

The Yankees Are Winning in Spite of Aaron Judge

If you went back in time to March and told the New York Yankees that they would be 23-13 on May 6 even without Gerrit Cole, one assumes they'd be thrilled.

More interesting, though, would be their reaction upon hearing about Aaron Judge.

They'd probably assume his fingerprints would be all over the club's warm start. But they would, of course, be wrong. Judge does have seven home runs, but he's batting only .220 with a .350 OBP. For reference, his career marks are .279 and .393.

The weirdest thing is how not hard the 6'7", 282-pounder is hitting the ball. Everything is down relative to 2023, but nothing more so than his barrel rate. At 15.7 percent, it's well below the 27.5 percent mark he had last year.

It must also not go unnoticed that what power Judge, 32, is showing is concentrated almost exclusively to the opposite field. He's pulled only two fly balls to left field all season, compared to 44 times amid his 62-homer campaign from two years ago.

Again, that the Yankees are winning anyway is the good news. Nonetheless, it's hard not to wonder at this point if Judge's lingering right toe injury is more bothersome than he or the Yankees want to admit.

The Phillies' Best Pitcher Is...Ranger Suárez?

The Philadelphia Phillies boast an MLB-best 24-11 record, for which much credit is owed to what's arguably the league's best starting rotation.

That Zack Wheeler and Aaron Nola, who B/R's Tim Kelly considers the best starting duo in MLB right now, are both having terrific years is no great surprise. What is a surprise is that neither of them is necessarily the Phillies' best pitcher right now.

Because when a guy is doing what Ranger Suárez is doing, said guy deserves that kind of consideration.

It's not just that the left-hander is 6-0 with a 1.72 ERA and a league-best 0.72 WHIP through seven starts. It's also how legit it all seems. He's an excellent command artist who's stifling hard contact to the tune of 82.7 mph average exit velocity.

It likewise bears noting that the 28-year-old Suárez is not dominating in short stints. He's gone at least six innings in all but one of his seven starts, and he ranks fourth overall with 47 total innings.

In other words, what was supposed to merely be an ace duo in Philadelphia is actually a proper ace trio.

The Red Sox Are a Pitching Powerhouse

Speaking of pitching-related surprises, allow me to paint a picture of how hopeless the Boston Red Sox's mound staff looked coming into 2024.

Said staff posted a 4.52 ERA in 2023 even with Chris Sale, who got dealt to Atlanta just as Boston was signing Lucas Giolito. Who, naturally, had to have season-ending elbow surgery midway through spring training.

So, of course the Red Sox have the best ERA in the league at 2.61.

This is the club's new live-ball era low through its first 35 games of a season, and it's not as if there's a ton of good luck going on. Boston's walk rate and hard-hit rate have both taken dramatic turns for the better relative to 2023.

If this is nothing else, it's an interesting case study in the four-seam fastball possibly being overrated. Red Sox starters have only used the pitch 9.1 percent of the time, the lowest such mark on record.

What's for sure is that this would not be happening without chief baseball officer Craig Breslow and pitching coach Andrew Bailey. It's indeed happening because of them, and the result for now is a team with eyes on an unexpected playoff berth.

The A's and Nationals Are Actually Pretty Good

Let's all give ourselves credit for being right about the Chicago White Sox and Colorado Rockies.

I'm pretty sure we all expected them to be bad this year, and they are precisely that. Between them, they have 16 wins and 52 losses. Not pretty. Not pretty at all.

But in the tradition of turnabout being fair play, we must now admit how wrong we all were about the Oakland Athletics and Washington Nationals.

They combined to lose 203 games in 2023, and the general expectation was that more of the same was in order for 2024. And not just for us human beings, as projection systems typically saw them as bottom-four teams for the coming season.

But with the A's at 17-18 and the Nats at 17-17, what they actually are is collectively one game under .500. Both have real breakouts going on, as A's closer Mason Miller has (literally and figuratively) blown everyone away and CJ Abrams is rising in the ranks of MLB's best shortstops.

I won't go so far as to say we should have seen this coming. But now that Oakland and Washington are where they are, there's nothing wrong with enjoying it while it lasts.

Even Sans Shane Bieber, the Guardians Are Elite

The Cleveland Guardians likewise came into this season with relatively little hype, but that was as much on them as it was on anyone else.

They only went 76-86 in 2023, and their offseason consisted of doing a whole lot of nothing. According to FanGraphs, their chances of winning the AL Central were about half as strong as those of the defending champion Minnesota Twins.

And yet, there the Guardians are on top at 22-12.

It should feel like overachieving, but the Guardians aren't overperforming relative to their run differential and they've even had a difficult schedule so far. So, maybe they're just good?

They're definitely better in some key areas, particularly offensively even with José Ramírez still struggling to help breakout star Josh Naylor carry the lineup. And the bullpen? It's nasty. Nastier, even, than its 2.54 ERA lets on.

It's fair game to worry about Cleveland's rotation, which has already lost Shane Bieber for the year and is otherwise still missing Gavin Williams. But with the way they're playing, a sixth playoff berth in the last nine seasons may be in order anyway.

Both Central Divisions are Blowing Away Expectations

It is, of course, not just the Guardians who are buoying the AL Central in 2024. And the NL Central isn't too shabby either.

To even note as much feels a little like dividing by zero. The Central divisions were the two worst divisions in baseball last year and more of the same was supposed to be on tap for 2024. It had basically been decreed.

But if we're going off collective winning percentages, they're actually two of the best divisions right now:

1. AL East: .553
2. NL Central: .515
3. AL Central: .515
4. NL East: .509
5. AL West: .461
6. NL West: .446

The Guardians are obviously doing their part, but also over .500 in the AL Central are the Twins, Kansas City Royals and Detroit Tigers. The NL Central, meanwhile, has two 20-game winners in the Milwaukee Brewers and Chicago Cubs, plus a Cincinnati Reds club that's in the wild-card hunt at 16-18.

There's plenty of potential unsustainability at play here, but also much-improved units (i.e., Milwaukee's offense and Kansas City's pitching) and rising stars (i.e., Elly De La Cruz, Shōta Imanaga and Tarik Skubal). And at this point, it's just a matter of time before the latter roster is further expanded by Paul Skenes joining the Pittsburgh Pirates.

Clearly, it's time to take the 2023 Central playbook and put it where it belongs: the garbage.

The Astros Are Legitimately in Trouble

The Houston Astros have been on a nice run of late, winning five out of eight to make a move up the AL West standings.

As in, a move from solely in last place to merely tied for last place.

That the Astros would only be 12-22 through 34 games is something nobody expected, but that's nonetheless where they are and it's fair game to be legitimately worried about it. Per FanGraphs, their chances of making the playoffs have dropped from 86.2 to 44.9 percent since Opening Day.

"Nothing against them, just other teams have youth and have passed them," one AL executive told MLB.com's Mark Feinsand. "They have aged and don't have the pitching."

No kidding. The Astros have already had to send 2020 AL MVP José Abreu to the minors just to keep him from further embarrassment in the majors. And while their pitching staff has been getting healthier of late, it still only has a 4.75 ERA.

The "All good things must come to an end" vibes are palpable. And if they keep up, the Astros might not even make the playoffs, much less go as far as the American League Championship Series for the eighth time in as many years.

Stats courtesy of Baseball Reference, FanGraphs and Baseball Savant.