Stacking is an integral part of daily fantasy baseball. Correlation drives upside, giving your lineups a slate-winning ceiling when your stacks explode.

This piece will do the digging and the dirty work each day to determine which stacks are worth rostering on FanDuel's main slate. While we want upside, we also need to factor in game theory, especially in a sport as random as baseball.

Our MLB DFS heat map is a quick way to get a feel for the overall slate and which offenses are in a good spot. You can also check out our daily fantasy baseball projections to identify the slate's best bats.

Let's look at the top stacks for this main slate.

Toronto Blue Jays

We have one of our first noticeably high implied team totals of the season, and that's no coincidence based on the weather we're expecting in Kansas City.

Not only does the forecast show temperatures touching nearly 80 degrees, but we're also getting 20-plus mph winds blowing out to left field. Add in a below-average pitcher facing the Blue Jays' potent offense, and we get a slate-best 5.54 implied team total.

Left-hander Kris Bubic is taking the mound for the Royals, and he's been mediocre-to-poor across his three MLB campaigns. In 2022, he submitted a 4.77 SIERA, 18.7% strikeout rate, and 10.7% walk rate, and he also produced the lowest ground-ball rate of his career (41.0%).

Toronto's projected lineup has eight right-handed batters, but even if we get a few more lefties, it shouldn't matter because Bubic was actually worse in same-sided matchups. In the split, he was rocked for a 5.60 xFIP, 13.4% strikeout rate, and 12.7% walk rate, and this doesn't appear to be a fluke, as he's struggled versus lefties throughout his career.

This is one of those lineups that truly can be stacked from top to bottom, and while George Springer ($3,800), Bo Bichette ($3,900), and Vladimir Guerrero Jr. ($4,000) are great if you can fit them in, we can create value stacks involving Alejandro Kirk ($3,000), Matt Chapman ($3,000), Whit Merrifield ($2,800), and Danny Jansen ($2,500) without skimping much on upside.

Daulton Varsho ($3,500) is the only left-handed batter projected to start, and while he has poor career numbers in lefty-lefty matchups, he's worth considering in this matchup if he remains in the cleanup spot.

Boston Red Sox

Boston's pitching continues to let them down, but some hot hitting has helped them stay in games thus far. They've plated 9, 9, 9, and 6 runs over their first four games, and another strong performance could be on tap tonight.

Although Pittsburgh right-hander Roansy Contreras produced respectable overall results in 2022, a 9.6% walk rate would often come back to bite him, and a 36.4% ground-ball rate left him open to the home run ball.

But what should really pique our interest is his weak splits versus lefties. Against left-handed batters, Contreras produced a 5.01 xFIP and 18.3% strikeout rate, and he allowed 1.38 home runs per nine innings off a 47.9% fly-ball rate.

Several of Boston's lefty batters cashed in with big fantasy scores last night, and we shouldn't hesitate to go right back to Rafael Devers ($4,000), Alex Verdugo ($3,400), Masataka Yoshida ($3,200), and Triston Casas ($2,800) as primary building blocks in Sox stacks. Yoshida slugged his first round-tripper on Monday night, which is hopefully a sign that he'll be able to hit for some power this season.

Contreras was more effective in same-sided matchups last year (4.13 xFIP; 23.0% strikeout rate), so the Boston righties could have a tougher time getting going. But none of them have particularly high salaries if you sprinkle them in to attack what projects to be a weak Pirates bullpen.

St. Louis Cardinals

As of this writing, outside of the Blue Jays, we have two other teams cracking five implied runs in their team totals between the Cardinals and Rays, and both are also being aided by warm, hitter-friendly temperatures.

But we'll highlight St. Louis here because there's a chance that they'll also have 18 mph winds blowing out to left, to further boost offense.

The Cardinals' pitching matchup is a wild card, though, as we'll be seeing Atlanta southpaw Dylan Dodd make his first MLB start. Dodd has very little experience against high-level competition, with just one Triple-A start and nine Double-A starts under his belt. Although he showed encouraging strikeout numbers in his rise up the ranks, preseason projections on FanGraphs all view Dodd as a below-average pitcher with a sub-20.0% strikeout rate this season.

At the same time, the 24-year-old performed well in spring training, so it's quite possible he blows past those projections in a breakout year.

But even if Dodd pitches above expectations tonight, this is a brutal matchup for him even without the weather factoring in. The Cardinals project as a rough, rough opponent for left-handers, as their active roster boasts a league-best 144 wRC+ versus southpaws dating back to last season.

While that number should level off a bit as the season goes along, this lineup will be loaded with tough right-handed hitters tonight, as Paul Goldschmidt ($4,000), Nolan Arenado ($3,800), and Willson Contreras ($3,100) form a dangerous trio in the heart of the order. All three surpassed a .220 ISO last season, and that ballooned to over .300 apiece versus left-handed pitching specifically.

Other righties like Tyler O'Neill ($3,500) and promising rookie Jordan Walker ($2,500) could potentially move up the lineup, and Juan Yepez ($2,500) might get a start, giving us several ways to go in stacks.