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.

The MLB DFS heat map at numberFire 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 -- which are powered by numberFire -- to identify the slate's best bats.

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

MLB DFS Stacks

Pittsburgh Pirates

Implied Total: 4.89 | Opposing Pitcher: Trevor Williams

In 2023, the Washington Nationals asked Trevor Williams to become a fulltime starter again, leading to him starting 30 games during the year -- the second most of his career and his most since 2018. The season was not especially kind to him. Over 144.1 innings, he surrendered the most home runs in the National League (34) while posting a 5.55 ERA and 1.60 WHIP.

We picked on Williams in fantasy for a full season last year, and we'll probably do it again in 2024. That means the Pittsburgh Pirates should be on your radar for Wednesday's DFS contests.

Interestingly, the Pirates have yet to face a right-handed starter this season -- they squared off against left-handers in each of their first five games. That means we won't have a perfect picture of their lineup ahead of today's game, but we can still make some solid inferences about potential platoons.

For example, keep Jack Suwinski ($2,700) and Rowdy Tellez ($2,700) in mind as lower-salaried options for the Pirates. Both power-hitting left-handed batters have seen limited reps this season given the Pirates' strange schedule but could see expanded workloads tonight against Trevor Williams. Projections at numberFire have both players slated for more than 11 FanDuel points.

If you're going with Pirates, you'll obviously want to consider Oneil Cruz at his $3,500 salary. The major breakout candidate has a shot to notch his first homer since Opening Day in this one and has managed a solid .855 OPS so far. His +330 odds to hit a home run are the shortest among the Pirates' players, with Tellez and Suwinski trailing just behind him at +340 odds.

Bryan Reynolds ($3,600) has the highest projected FanDuel points among the Pirates at 15.4 and has hit second in each game so far this season. He has a good chance to pick on Williams near the top of the Pirates' lineup.

The Pirates even have a catcher we can potentially use here -- Henry Davis ($2,700) is now catcher-eligible on FanDuel and is projected for 10.5 FanDuel points, tied for the most at the position on the slate. The former first overall pick was electric this spring, notching 4 homers to go with a .310 batting average before the season began.

The D.C. area is seeing some rain, so you'll want to monitor this game closely ahead of first pitch, but if they do get cleared to play, you'll want to keep the Pirates in mind for any stacks tonight.

On a related note, the weather at Wrigley Field is expected to be gross, meaning there's a chance the Chicago Cubs' game against the Colorado Rockies gets postponed. If they do end up playing through rainy conditions and cold weather, though, you'll want to consider stacking some Cubs in your lineup against Cal Quantrill. The Rockies' pitching staff looks pretty awful -- evidenced by their league-worst 8.17 runs against per game -- making them an appealing team to target with stacks whenever they're on the slate.

Houston Astros

Implied Total: 4.84 | Opposing Pitcher: Chris Bassitt

The Houston Astros endured a rough 0-4 start to the season but appeared to vent their frustrations on the Toronto Blue Jays to start their three-game series -- the Astros notched 10 runs in the series-opening win and recorded 8 more hits in their loss last night.

Blue Jays starter Chris Bassitt looked pretty rough in his own season debut. Against the Tampa Bay Rays, he lasted 5 innings, giving up 6 hits, 2 walks, 4 earned runs and a home run in the 8-2 drubbing. He allowed uncharacteristically high marks in exit velocity (91.3 MPH) and hard-hit rate (53.3%) as well. It was one outing at the start of the season, so we don't want to take too much away from it -- but it does make us feel a little better about stacking the Astros today in DFS.

It's also worth pointing out that the Blue Jays' bullpen doesn't look especially sharp to start the year -- especially with both Jordan Romano and Erik Swanson on the injured list. They've posted a 5.30 skill-interactive ERA (SIERA) on the season so far, which ranks second worst in the game. It hasn't bitten them too hard yet, but their league-worst 13.4% strikeout rate as a unit could be a precursor to some future late-game meltdowns while their top bullpen arms are sidelined.

Yordan Alvarez ($3,900) is projected for the most FanDuel points (15.5) of any player on tonight's slate. He's a great foundational piece to construct a stack around and could snap his cold streak in this one. Alvarez has had Bassitt's number in their previous meetings, with as many homers (4) as strikeouts (4) and a casual 1.486 OPS.

Jose Altuve is off to another strong start this season, with two homers in his last three games. He has a $3,700 salary for tonight's contests and is projected to score 13.1 FanDuel points. As the Astros' leadoff hitter, he offers both home run upside and high correlation with Alvarez if Yordan does pop off.

We all know familiar names such as Kyle Tucker ($3,600) and Alex Bregman ($3,000), but it's worth pointing out two younger names at the back end of Houston's lineup -- Jeremy Pena ($2,600) and Yainer Diaz ($2,800). The Astros' young shortstop and catcher are having fantastic early seasons at the plate and trail only Tucker in RBI to date among Astros. Hitting behind stars gives Diaz and Pena RBI upside with each plate appearance, and having guys like Altuve and Alvarez around should eventually help them reach home more often themselves.

Los Angeles Dodgers

Implied Total: 4.72 | Opposing Pitcher: Kyle Harrison

The Los Angeles Dodgers' offense looks scary right now. Their 6.5 runs per game ranks fourth-best in the majors -- and two of the teams they currently trail have had the benefits of playing against the Rockies and the Chicago White Sox.

We can't really go any further without giving credit where it's due -- Mookie Betts is the MVP of the league so far this year. The future Hall of Famer has an MLB-best 1.772 OPS on the year with 5 homers. With how he's playing, you have to consider him in any lineup -- even with his prohibitive $4,800 salary.

San Francisco Giants left-hander Kyle Harrison notched a win in his first start of the year but surrendered a pair of solo home runs to the San Diego Padres in that one. The Padres registered a 91.6 MPH average exit velocity against him as well as a 50% hard-hit rate and a 50% fly-ball rate.

It was one game against a good lineup, but Harrison might be a pitcher who will struggle at preventing the long ball. In the 34.1 innings he pitched as a 21-year-old rookie last year, he gave up an extrapolated 2.1 homers per 9 innings.

Speaking of homers, Teoscar Hernandez ($3,500) is hitting them at a high rate against lefties this year. He's up to two dingers on six plate appearances against left-handers and is a great piece to LA stacks.

Left-handed sluggers Shohei Ohtani ($4,200) and Freddie Freeman ($4,000) are always a threat to go yard, even against left-handed pitchers -- Ohtani has a career .825 OPS versus lefties while Freeman's career rate sits at .808.

If catcher Will Smith ($3,300) suits up tonight, he could have a good outing -- he is projected for 10.5 FanDuel points. The arrival of Ohtani has limited Smith's opportunities to operate as the Dodgers' designated hitter on his off-days from catching, though, so he's not a lock to make the lineup tonight after starting the last two games behind the dish.

If you're looking for a lower-salaried right-handed bat to capitalize on Harrison's susceptibility to homers, consider Chris Taylor ($2,500). The veteran hasn't found his stride yet in 2024 but could have a nice night against Harrison. He hit fifth the last time LA saw a southpaw.

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The above author is a FanDuel employee and is not eligible to compete in public daily fantasy contests or place sports betting wagers on FanDuel. The advice provided by the author does not necessarily represent the views of FanDuel. Taking the author's advice will not guarantee a successful outcome. You should use your own judgment when participating in daily fantasy contests or placing sports wagers.