MLB Predictions and Moneyline Picks for Friday, Aug. 21

Colby Marchio - Contributor at Covers.com
Colby Marchio • Betting Analyst 7+ years betting experience
Updated: Aug 21, 2026 , 02:08 PM ET • 4 min read

Friday’s moneyline predictions are loaded with favorites, with a few underdogs sprinkled in.

Jordan Walker St. Louis Cardinals MLB
Photo By - Reuters Connect. St. Louis Cardinals outfielder Jordan Walker high fives teammates.

Here are my MLB moneyline predictions for tonight's slate, which include the Cardinals at plus money on the road against the Phillies.

Before we dive in, be sure to check out all of our MLB picks for Friday, Aug. 21.

MLB moneyline picks for August 21

Matchup Pick
Braves Braves
vs
Brewers Brewers
Brewers
-137
Cardinals Cardinals
vs
Phillies Phillies
Cardinals
+226
Blue Jays Blue Jays
vs
Yankees Yankees
Blue Jays
+173
Giants Giants
vs
Red Sox Red Sox
Red Sox
-175
Nationals Nationals
vs
Marlins Marlins
Marlins
-148
Rays Rays
vs
Orioles Orioles
Orioles
-121
Mets Mets
vs
White Sox White Sox
White Sox
-142
Athletics A's
vs
Astros Astros
Athletics
+158
Tigers Tigers
vs
Royals Royals
Royals
-103
Angels Angels
vs
Rangers Rangers
Angels
+124
Guardians Guardians
vs
Rockies Rockies
Guardians
-148
Reds Reds
vs
Diamondbacks Diamondbacks
Diamondbacks
-142
Twins Twins
vs
Padres Padres
Padres
-121
Cubs Cubs
vs
Mariners Mariners
Cubs
+101
Pirates Pirates
vs
Dodgers Dodgers
Dodgers
-219

Prices courtesy of Polymarket as of 8-21.

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Expert MLB moneyline picks for August 21

Braves vs Brewers: Brewers (-137)

Brewers win probability: 57%

In a matchup featuring two superstar starters, I only care about which offense has been struggling. By far, the Atlanta Braves’ bats have been frozen solid over their last 12 games, as they own a .267 wOBA, 68 wRC+, and .133 ISO during that stretch. The Brewers look strong all around, making -137 a very reasonable price to pay.

Cardinals vs Phillies: Cardinals (+226)

Cardinals win probability: 30%

Strictly based on the moneyline price, why would you pay $2.52 for a team to win a ball game? Especially with how well the Cardinals have been playing, owning a 121 wRC+, .769 OPS, and .343 wOBA over their last six outings. Additionally, Hunter Dobbins has been lights out, posting a 2.93 ERA, 2.69 xERA, and 1.19 WHIP over his last five starts. Dobbins has also done an incredible job limiting hard-hit and barreled balls during that stretch.

Jesus Luzardo and the Phillies have been great, but it's the Cardinals or nothing at +2226.

Blue Jays vs Yankees: Blue Jays (+173)

Blue Jays win probability: 34%

I'm fading Cam Schlittler in this spot, as he's been allowing far too much hard contact at home and over his last five starts. So far this season at home, the Yankees’ young star pitcher owns a 4.11 ERA while allowing a 47% hard-hit rate and 12.4% barrel rate. Over his last five starts, he's still allowing a hard-hit rate above 46%.

On top of that, the Blue Jays’ offense has finally awakened from its coma. The team owns a 126 wRC+, .807 OPS, and .354 wOBA over the last six games. Despite the Yankees’ solid series against the Orioles, they're still putting up lifeless numbers at the dish.

Blue Jays or nothing at those prices.

Giants vs Red Sox: Red Sox (-175)

Red Sox win probability: 62%

We have ourselves a good old-fashioned pitching duel between Logan Webb and Sonny Gray this evening in Boston. Both pitchers enter Friday night with impressive numbers over their last five starts. However, one side is producing far better than the other offensively. The Giants have put a 25% strikeout rate, .596 OPS, and .118 ISO over their last six games. Meanwhile, the Red Sox have produced a sub-20% strikeout rate, .763 OPS, and .338 wOBA across their last six.

Trust the hotter bats. Take the Red Sox to come out on top.

Nationals vs Marlins: Marlins (-148)

Marlins win probability: 58%

Ryan Gusto takes the mound for the Fightin' Fish this evening, and he's been rather impressive across his past three starts, posting a 3.07 ERA, 2.99 xERA, and 1.02 WHIP. The Miami Marlins' bats have awakened, too, with the team owning a 113 wRC+ over its last 12 outings.

Meanwhile, the Nationals have just a 60 wRC+, .253 wOBA, and .553 OPS over their last six matchups. With how well Gusto has been playing, the sub-$1.50 price is worth it this evening.

Rays vs Orioles: Orioles (-121)

Orioles win probability: 54%

It's hard to overlook Freddy Peralta's struggles since joining the Rays. The veteran owns a 7.53 ERA and 1.47 WHIP while allowing nearly 50% hard contact and a barrel rate above 13% with Tampa. He draws an Orioles lineup coming off a tough series against the Yankees. But all Baltimore has done this past week is generate hard contact, which makes the Birds the more intriguing side this evening.

Mets vs White Sox: White Sox (-142)

White Sox win probability: 58%

Sean Manaea enters Friday owning a 4.33 xERA while allowing nearly 50% hard contact and an 11.11% barrel rate to opposing hitters over his last three outings. The Chicago White Sox have dealt with left-handed pitchers very well this season, and with Sean Burke on the bump this evening playing some of his best baseball at home, the White Sox are the play in this matchup.

A's vs Astros: A's (+158)

A's win probability: 38%

The Athletics have boasted the far more efficient offense over the last few weeks compared to the Astros, who own just a 72 wRC+ over their last 12 games. The Athletics, in that span, have a 115 wRC+, .335 wOBA, and .760 OPS. Additionally, J.T. Ginn has some strong underlying metrics pointing toward progression, sporting a 3.37 xERA while allowing little to no barreled balls over his last five starts.

At +158, the Athletics are a strong lean.

Tigers vs Royals: Royals (-103)

Royals win probability: 48%

Snagging the Royals at near plus money is the lean here. Their bats have been hot this past week, while the Tigers haven't looked great since before their series against the White Sox. Detroit has lost five of its last six games, and the club's offensive numbers show a team that has gone cold at the dish.

Troy Melton has been great for the Tigers this season, but Detroit's offense is scuffling too much. Royals or nothing.

Angels vs Rangers: Angels (+124)

Angels win probability: 43%

These two lineups have been dreadful. However, this game has pitching duel written all over it, with Reid Detmers and MacKenzie Gore on the bump. Detmers has been nails in his last five outings while posting a 35% strikeout rate. The Rangers have produced a 26.7% strikeout rate over their last six games. Detmers can exploit that. 

Guardians vs Rockies: Guardians (-148)

Guardians win probability: 59%

Joey Cantillo is due for another incredible outing against a lineup that's been struggling mightily with striking out against left-handed pitching. Elsewhere, the Rockies have Tanner Gordon on the bump, and he owns a 4.60 xERA over his last three starts while allowing over 52% hard contact.

With how poorly the Rockies have been, there's nothing intriguing about backing them here.

Reds vs Diamondbacks: Diamondbacks (-142)

Diamondbacks win probability: 58%

The Reds have maintained a sub-60 wRC+ over their last 12 games. Nick Lodolo starts for them tonight, and he owns a 4.95 xERA across his last five appearances. There's nothing sexy about this Reds team.

Arizona has been on fire at the dish and should have no problem exploiting Lodolo’s flaws. Plus, Eduardo Rodriguez has been great all season long.

Twins vs Padres: Padres (-121)

Padres win probability: 53%

Fade Connor Prielipp day!

The Twins' left-hander has been struggling across his last three starts, posting an 8.22 ERA, 1.76 WHIP, and 14.29% walk rate. With how hot the Padres’ bats have been, San Diego should step on the gas even more once the Twins turn to their bullpen. Minnesota’s pen has put up a 4.06 xERA on the year.

Take the hometown team here.

Cubs vs Mariners: Cubs (+101)

Cubs win probability: 50%

Sure, Matthew Boyd is a punching bag at times, but when are we going to get another chance to snag the Chicago Cubs at plus money against a subpar team like the Mariners? Emerson Hancock has been great all season, but facing this lethal Cubs lineup could be one of his biggest tests on the season. At +101, it's well worth the risk.

Plus, Seattle’s offense has been lifeless all season long. Their recent form means nothing.

Pirates vs Dodgers: Dodgers (-219)

Dodgers win probability: 68%

It's not fun to write Dodgers moneyline -219 when the price is that high, but the Pirates have been subpar offensively, posting a 91 wRC+ over their last 21 games while owning just a .657 OPS and .120 ISO. That lineup now draws Yoshinobu Yamamoto. Good luck.

The 2025 World Series MVP has been stellar over his last five outings, posting a 1.82 ERA and 0.84 WHIP. Bubba Chandler can have his best day of the season, and Yamamoto will still put up a better one.

Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
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Colby Marchio
Betting Analyst

Colby Marchio is a two-time DePaul alum and former Division 1 (club) baseball player who has been sports betting since 2019. Since graduating in 2021, he has worked throughout the media circuit, hosting and appearing on various television and radio shows while making countless guest appearances discussing Major League Baseball, college basketball, college football, and the National Football League.

A self-proclaimed numbers nerd, Colby may enjoy digging through the data even more than winning itself. That passion is why his two favorite sports to cover are college basketball and Major League Baseball. 

As for his favorite sportsbook, it is whichever one has the best price, or whichever one is not taxing him as an Illinois resident. 

You can find all of his plays and more @ColbyMBets on Twitter/X.

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