The 2018 season is upon us. There are a million different ways it could play out. That's not going to stop us from giving you seven data-based guarantees for trends, records and facts you'll almost certainly see this season.
1. The Yankees will break the team home run record.
Though baseball's homer record fell in 2017, the team mark did not. The 1997 Mariners still hold the all-time team record at 264. That's going to change. Probably.

We wrote about this in detail last month, when we noted that the 2017 Yankees already led the Majors in homers with 241, and then they went out and added Giancarlo Stanton anyway. At the time, that was enough to put them into the conversation for the record, but they've made two more moves since then, adding Brandon Drury and Neil Walker, who combined to hit 27 homers last year. That should take time away from the light-hitting bats of utility infielders like Ronald Torreyes and Tyler Wade.
Maybe the question here isn't about if the Yanks will break the record. Maybe it's more about when they break the record. Is it too much to wonder if it happens before the end of August?
2. The "air ball revolution" will continue.
There are a few factors that have led to more home runs across baseball, and one is the "air ball revolution" that has been detailed so often here and elsewhere. As stars like Justin Turner, Daniel Murphy, J.D. Martinez and Josh Donaldson have found great success in large part due to trying to hit the ball in the air, other players have followed. Last year, it was Chris Taylor and Yonder Alonso. In 2018, we've already heard about Yasmani Grandal and Juan Lagares trying it, plus more who have likely done so quietly.
We've seen it in the data. The ground-ball rate has fallen from 45.3 percent to 44.7 percent to 44.2 percent over the past three years. Launch angle has risen from 10.1 degrees to 10.8 to 11.1 degrees in the same time. You don't hear about hitters trying to hit the ball on the ground more, do you?
3. The fastballs you see will be thrown even harder, and higher ...
Part of why we've seen more strikeouts across baseball is because hitters don't care about them like they used to, but part of it is because pitchers simply throw so much harder than they used to.
 
In 2008, the first year of reliable pitch-tracking technology, fastballs averaged 91.8 mph. Last year, that mark was at 93.6 mph. If that doesn't sound like a big gain, think about it this way -- in '08, just 70.4 percent of fastballs were thrown over 90 mph, while in '17, nearly 86 percent were.
You'll also be seeing more of those hard fastballs thrown high as teams work to counteract the ability of hitters to elevate the ball. We've been talking about this for a few years, with Justin Verlanderin 2015 and the Dodgers' bullpen last year, and now teams like the Cardinals are openly talking about throwing high in the zone more often.

This is a trend we already saw some of as 2017 went on. In April, 53.6 percent of four-seam fastballs were thrown "high" (which we define as reaching the plate 2.5 feet above the ground or higher). That consistently increased as the year went on -- presumably a September dip can be attributed to expanded rosters -- and when the games mattered the most, in October, it was up to 59 percent.
4. ... but you'll see fewer fastballs in general.
Speaking of trends you may not have noticed, but take a look at how steadily the rate of fastballs (defined as four-seam, two-seam and sinker) has dropped in the Majors, down to 2017's rate of 55.3 percent.

It's not just about curveballs, but it's largely about curveballs. It's difficult to look at last year's list of top curveballing clubs and not notice that the top five teams all made the postseason: the Indians, Red Sox, Dodgers, Astros and Cubs. With evidence that hitters have been hunting fastballs for home runs, this is another way that pitchers are trying to keep the ball in the park.
5. Starting pitchers will work even fewer innings.
The Rays' experiment with a four-man rotation and a regular bullpen game may or may not work, though there's an argument to be made that "a bullpen game" and "a fifth starter who goes 3 2/3 innings" is basically the same thing anyway. But it really is an indication that the blurring of the lines between starters and relievers will continue, which we've been talking about for some time.
We saw this last year, when the Dodgers and Astros each refused to push their starters too deep into games, both as a concession to the "third time through the order" penalty and in hopes of improving health. As you can see, the percentage of innings taken up by starters over the past four decades held relatively steady in the 65-70 percent range ... right up until 2015.

That year, it dropped from 66.5 percent to 65 percent. The next year, that was 63.3 percent. And last year, it was 61.9 percent, an all-time low. It's not at all unreasonable to think that in 2018, we'll see starters taking up fewer than 60 percent of innings for the first time ever.
6. The catcher who qualifies for the batting average title will be an endangered species.
Let's talk about the 21st century. In 2000, seven catchers (defined here as a player who spent 75 percent of his time behind the plate) received 502 plate appearances. In '04, it was 11; in '08, it was nine. In the first 17 seasons of the 21st century, that number was between six and 11 every year.

Until, that is, 2017. Last year, only three catchers had 502 plate appearances: Yadier Molina, J.T. Realmuto and Gary Sanchez. That's the second fewest in any non-strike season dating back to 1969. Even Sanchez only got there with 18 games at designated hitter, and in '18, it's easy to see the 35-year-old Molina ceding enough time to Carson Kelly to not get to 502.
Due again to reasons of fatigue and health, teams no longer view catcher as a "one-man" job. Look at the Dodgers, who split the backstop position between two very good catchers in Grandal (482 plate appearances) and Austin Barnes (262), or the Braves, who did the same with Tyler Flowers (370) and Kurt Suzuki (309). Maybe Salvador Perez or Willson Contreras or Buster Posey will stay healthy enough all year long to get there in 2018; if they do, they'll be the exception, not the rule.
7. The Astros will be the best team in baseball, but the Indians will win the most games.
It cannot be overstated how good the Astros look to be, since they're not only the defending champs, they've added Gerrit Cole and might have a historically good lineup. They're going to be universally picked to win the American League West, and with good reason: They're the best team baseball has to offer.
That said, the AL West got a lot better this year. The Angels added Shohei Ohtani, Ian Kinsler and Zack Cozart; the Rangers completely remade their pitching rotation; the A's are quietly one of baseball's most interesting teams, even before they added Jonathan Lucroy. Meanwhile, Cleveland is also one of the best teams in the game, but they're sharing a division with rebuilding clubs in Chicago, Detroit, and Kansas City.
One way to quantify this is to look at the 2018 win projections. The four non-Houston teams in the AL West are projected to win 80.5 games apiece, while the four non-Cleveland teams in the AL Central have a projected average win total of just 72.3. Projections aren't everything, and the Astros might be so good that it just doesn't matter, but if we're going to be bold, this is how we're doing it.