Stacks are the backbone of cashing daily fantasy baseball lineups. Correlation drives upside, creating the potential to place high or even win GPPs when your selected stacks explode offensively.

This column will do the digging and the dirty work to determine which stacks are worth rostering each day. Scoring upside will fuel the stacks that get the nod. Sometimes that will lead to chalky selections, but contrarian stacks will get their fair share of love too.

In addition to utilizing the touted daily stacks in handbuilt lineups, numberFire premium members can throw these highlighted stacks into an optimized lineup using our DFS Sharpstack tool. Our hitting heat map tool is also available to premium members looking for more stacking options. It provides valuable info such as implied total, park factors, and stats for identifying the quality of the opposing pitcher.

Let's take a look at the top stacks on today's main slate.

Houston Astros

Each of the stacks I'm plugging today are facing a lefty, and the Houston Astros are my favorite of the bunch.

According to FanGraphs, the Astros rank first in weighted runs created plus (128 wRC+) against lefties this year. They're also the hottest offense in baseball, leading the way with a 127 wRC+ over the last 30 days.

Their matchup is a plus tonight in favorable hitting conditions. Eduardo Rodriguez has a 5.59 ERA this year, albeit with a much better 3.50 skill-interactive ERA (SIERA). E-Rod has been knocked around by lefties and righties alike, yielding a .348 weighted on-base average (wOBA) to lefties and a .353 wOBA to righties in 2021. As for the hitting conditions, according to the park factors at FantasyPros, Fenway Park has the third-highest park factor for runs (1.103) and ranks first for doubles (1.404).

As is often the case when I suggest stacking the Astros, I'll acknowledge this lineup has impressive stacking depth. Five of their projected starters have a 132 wRC+ or higher against lefties since 2018. There is a bevy of options to pick from, including lefty-hitting outfielders Michael Brantley ($2,500), Yordan Alvarez ($3,300), and Kyle Tucker ($3,200). The infield is stacked with options, too, including Jose Altuve ($4,300), Carlos Correa ($3,700), Alex Bregman ($3,600), and Yulieski Gurriel ($3,400). Feel free to mix and match as you build four-man Houston stacks.

Chicago White Sox

The Chicago White Sox are tied for second in wRC+ (127) against lefties this year. They also rank tied for fourth in isolated power (.190 ISO) against southpaws, bringing even more power to the table than the aforementioned Astros.

In addition to being adept at hammering lefties like the Astros do, the Pale Hose are another white-hot offense, ranking third in wRC+ (119) over the last 30 days. Hyun-jin Ryu offers a more formidable opponent, but he is coming off of his worst start of the year, coughing up seven runs (six earned) on seven hits, two homers, three walks, and one strikeout in 5 2/3 innings against the Astros. Also, Guaranteed Rate Field is a launching pad, sporting the seventh-highest park factor for homers (1.131).

This is another lineup with exceptional stacking depth. Their projected lineup has six players with a 132 wRC+ or higher since 2018 (or since debuting in the case of a trio of young hitters). Narrowing down to my favorites, Andrew Vaughn ($2,200), Jose Abreu ($3,300), Tim Anderson ($3,800), and Yermin Mercedes ($2,200) get the nod.

Vaughn has terrorized lefties in his rookie season. In 56 plate appearances in the split, he's amassed a .411 on-base percentage, .426 ISO, and 207 wRC+. Even if you opt to use other stacks, I strongly suggest plucking Vaughn from this lineup as a standalone play.

Toronto Blue Jays

Opposing the White Sox is the Toronto Blue Jays. They haven't been the same caliber of offense against lefties as the Astros and White Sox have. But saying that, they're above-average in the split, ranking tied for 12th with a 104 wRC+. They're also the second-hottest offense over the last 30 days, sandwiched between the Astros and White Sox, boasting a 126 wRC+ and a .199 ISO during that time.

They have a favorable matchup tonight and the same homer-friendly park conditions that the White Sox get. Dallas Keuchel is responsible for a 4.25 ERA and 4.54 SIERA in a dozen starts across 65 and 2/3 innings. He's also a pitch-to-contact hurler, striking out only 12 percent of the batters he's faced this year.

My favorite stacking options are burgeoning superstars Vladimir Guerrero Jr. ($4,400) and Bo Bichette ($3,500). With that said, don't sleep on outfielders Teoscar Hernandez ($3,000), Randal Grichuk ($2,700), and Lourdes Gurriel ($2,500). Facing lefties this year, Hernandez has a gaudy .371 ISO, and Grichuk isn't far behind with a .327 ISO.

Joshua Shepardson is not a FanDuel employee. In addition to providing DFS gameplay advice, Joshua Shepardson also participates in DFS contests on FanDuel using his personal account, username bchad50. While the strategies and player selections recommended in his articles are his/her personal views, he/she may deploy different strategies and player selections when entering contests with his/her personal account. The views expressed in his/her articles are the author’s alone and do not necessarily reflect the views of FanDuel.