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

Houston Astros

Implied Total: 4.75 | Opposing Pitcher: Ross Stripling

Any time Ross Stripling is on the mound for the Oakland Athletics, we'll likely want to consider stacking the team he is going against. The Houston Astros are the next team who is slated to face Stripling, making them my favorite team to stack on Monday's main slate.

Stripling is sitting in the 82nd percentile in hard-hit rate (32.7%) and 90th percentile in barrel rate (3.3%), but he's in the 10th percentile in strikeout rate (15.3%) and 15th percentile in xBA (.281). For a pitcher who has permitted a barrel rate of 9.2% or higher in each of the previous three seasons -- and struggles to miss bats -- it's only a matter of time before Stripling's hard-hit rate and barrel rate increase.

Just his last time out, Stripling allowed 10 hits and five earned runs in only 1.2 innings of action versus the Texas Rangers. Despite the Astros having a 15-25 record, they have the lowest strikeout rate (17.0%), eighth-best wOBA (.320), and seventh-best wRC+ (108) against right-handed pitching this season.

Jose Altuve ($3,800), Kyle Tucker ($4,100), and Yordan Alvarez ($3,700) are the primary target in Houston stacks while Alex Bregman ($2,500) is a viable salary-saving option. Tucker has hit a homer in five of his last six games and has +450 odds to hit a home run on Monday.

While Jeremy Pena ($3,200) has four multi-hit outings in his last five contests, Yainer Diaz ($2,700), Jon Singleton ($2,600), and Joey Loperfido ($2,200) are other value options on the Astros. Loperfido has scored double-digit FanDuel points in three of the five games he's gotten three-plus ABs this year.

It wouldn't be the worst idea to stack both sides of this Athletics-Astros game as Spencer Arrighetti -- who is expected to start for Houston on Monday -- is in the 11th percentile in xERA (5.63), surrendering four-plus earned runs in three of his first five starts. The Athletics also have the ninth-best ISO (.159) and 12th-best wRC+ (102) versus right-handed pitchers.

San Diego Padres

Implied Total: 4.64 | Opposing Pitcher: Dakota Hudson

Another right-handed starter who is worth targeting with opposing bats when he's on the bump is Dakota Hudson of the Colorado Rockies. Hudson is in the 13th percentile or lower in chase rate (22.0%), whiff rate (19.1%), strikeout rate (12.4%), and walk rate (13.7%), which has led to him being in the 16th percentile in xERA (5.21).

Throughout his first seven starts, Hudson has given up three-plus earned runs in five of them. The one concern with stacking against Hudson is the fact he's a sinker-slider pitcher who has a 58.6% ground-ball rate and just a 25.9% fly-ball rate.

That being said, Hudson is also in the 33rd percentile in hard-hit rate (41.5%) and 30th percentile in average exit velocity (89.6 MPH). With the San Diego Padres hosting Hudson at Petco Park -- which has the third-highest home-run factor (133) to begin the year -- on Monday, they'll be one of the more popular teams to stack.

Although it's a small sample size, the Padres have the fifth-lowest strikeout rate (19.1%), 12th-best wOBA (.320), and eighth-best wRC+ (112) since acquiring Luis Arraez ($2,900) via trade. While Arraez should bat leadoff for San Diego on Monday, Fernando Tatis Jr. ($3,800), Jake Cronenworth ($3,000), and Manny Machado ($3,100) are the players who interest me the most.

Cronenworth is logging a .421 wOBA, .278 ISO, and 180 wRC+ against right-handed pitching.

Don't ignore Luis Campusano ($3,000) and Ha-Seong Kim ($3,000) at the bottom of the order in an advantageous matchup. Once Hudson -- who has pitched more than five innings just once in his last four starts -- exits the game, the Rockies' bullpen has the third-worst SIERA (4.30), worst WHIP (1.49), and second-lowest strikeout rate (18.5%).

Milwaukee Brewers

Implied Total: 4.26 | Opposing Pitcher: Mitch Keller

The idea of stacking against Mitch Keller on Monday is mostly about his noticeable home/road splits this season. Keller is sporting a 3.62 xFIP, 1.19 WHIP, and 23.6% strikeout rate at home compared to a 4.06 xFIP, 1.48 WHIP, and 18.3% strikeout rate on the road in his first eight starts in 2024.

Additionally, Keller is giving up a .305 wOBA and .383 SLG at home compared to a .369 wOBA and .500 SLG on the road. Regardless of where he's played, Keller is in the 19th percentile in hard-hit rate (44.5%), 29th percentile in average exit velocity (89.7 MPH), and 26th percentile in xERA (4.65).

Those metrics are worth noting as Keller is set to be the visiting pitcher versus the Milwaukee Brewers on Monday. Just a couple of weeks ago, Keller allowed six hits and four earned runs in five innings when taking on the Brewers at home.

Saving salary will be tough to do when stacking Milwaukee with Brice Turang ($3,100), William Contreras ($4,000), Christian Yelich ($3,900), Willy Adames ($3,600), and Rhys Hoskins ($3,300) all carrying salaries of $3,100 or higher. Yelich has multiple hits in three of his first four games back from injury, netting him 12-plus FanDuel points in three straight contests.

Where we can find value is at the bottom of the order, with Joey Ortiz ($2,600), Blake Perkins ($2,900), and Jackson Chourio ($2,900) standing out. There's also a chance we see Jake Bauers ($2,900) -- who has 18-plus FanDuel points in three straight appearances -- deployed in the lineup against a right-handed starter.

Try FanDuel’s Parlay Boost Builder on May 13th…eligible on all sports! Build a 3+ leg parlay, apply your Boost Builder, and get a 15% Profit Boost applied to your wager — with 10% added for each additional leg! See here for full terms and conditions. Learn about today’s other offers at FanDuel Sportsbook Promos.

Want to play MLB DFS? Head over to FanDuel’s daily fantasy baseball lobby to see all the offerings for today’s slates.

Sign up for FanDuel Sportsbook and FanDuel Daily Fantasy today!

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.