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Managers used to prize speed at the top of the lineup over just about everything else. Leadoff hitters needed to get on base too — preferably by rapping out a single, because swinging-and-missing was taboo. But once a leadoff hitter was standing on first, they needed to be able to steal second even when the pitcher and catcher knew they were going to take off.

But nowadays, managers want slightly more power out of their leadoff hitters, and they’re willing to trade some speed for it. A few modern No. 1 hitters can do it all, stealing bases and hitting home runs in equal measure. Mookie Betts of the Dodgers and Ronald Acuña Jr. of the Braves are great examples of this, but they are rare talents. More commonly, you will see a player like Marcus Semien atop the lineup, who gets on base with walks and hits with above-average power, in addition to his decent running speed.

The classic No. 2 hitter is all about “bat control.” That might mean hitting for a solid average, as Ozzie Smith, “The Wizard of Oz,” often did in his career. But it might also mean deliberately hitting the ball “behind the runner” to reduce the risk of a double play — or even to lay down a perfect sacrifice bunt. The important thing was to make sure the leadoff hitter got into scoring position for the big bats to drive in later. And a little speed from this spot never hurts, especially since it helps those ground balls turn into infield hits.

No place in the lineup showcases how the game has changed more than the No. 2 slot. Remember how the second spot in the order used to be all about making contact and moving runners over? Now, the data say that your best overall hitter should hit second rather than third, as originally believed. At the No. 2 spot, they will come to the plate more often, and less frequently with two outs. This is why better overall hitters — and especially better power hitters, like Trout, Seager, and Ohtani, hit in the 2-hole more than they ever did in the past.

The No. 3 slot was traditionally reserved for the best hitter, or more generally, the biggest star on the team. In the 3-hole, you were expected to hit for power and average, driving in the leadoff man if he was on base, or setting up the cleanup hitter for RBI chances of his own. It was a matter of pride for big names to bat in this slot.

However, as a result of research showing that top all-around hitters should bat second, the 3-hole has lost some of its prestige. Today’s No. 3 hitters are no slouches, of course. But as more players with a mix of elite skills get moved elsewhere, teams now tend to place greater focus on one particular attribute here, asking less of the role in terms of speed and other facets of the game.

Other than leadoff, this is the only spot with its own nickname: the cleanup hitter. That’s because No. 4 hitters “clean up the bases” by slugging home the runners in front of them. Historically, power has always been the most important attribute in the cleanup spot, with on-base percentage taking on less significance (the job of slots 1-3 was to get on base and set the table for the cleanup hitter). Even strikeouts were more tolerated here, if it meant a trade-off for more power. Cleanup hitters didn’t traditionally need to be fast.

But the cleanup role is changing a lot. It’s still a place for some teams to put burly sluggers, but the typical No. 4 hitter is now less powerful — and patient — than in the 1990s (it’s also getting very slightly faster on average, weirdly enough). No lineup slot has seen a bigger decline in Weighted Runs Created Plus — a measure of batting effectiveness relative to league average — than the cleanup spot.

Nos. 5-7 are where the lineup gets flexible. Managers often use those slots as lesser versions of the cleanup spot, perhaps featuring a power hitter with a poor batting average or a low walk rate. One traditional rule was also to alternate the handedness of these spots, depending on which side of the plate the cleanup hitter batted from. For example, a lefty No. 4 hitter would be followed by a righty No. 5, a lefty No. 6 and so forth. This ensured that the opposing manager couldn’t neutralize an entire block of the lineup with one reliever late in games.

In the modern game, these slots have undergone a surprising evolution, from a place for plodding sluggers to a spot to stash speedsters! As power bats have begun to take over the leadoff slot, batters who would have been leadoff hitters in an earlier era are increasingly moving down the order, often penciled in at Nos. 5-7 now.

In an earlier era of the game, slots 8 and 9 were defined by holding the worst hitters on the team. Back when National League pitchers hit, they would almost always hit ninth (except when oddball managers like Joe Maddon or Tony La Russa batted the pitcher eighth).

In the modern analytics era, these spots are gaining ground on the rest of the lineup, even after accounting for the absence of hitting pitchers. Already speedy, the 8th and 9th spots have gotten faster (again, you have to stash the batters who formerly would have hit leadoff somewhere), and AL No. 9 hitters walk more than ever — another sign that modern managers are spreading their batting talent more evenly throughout the lineup.