Best MLB prop bets Aug. 13: Back Pete Alonso and Max Muncy, fade Gavin Williams vs. Marlins

MLB prop bets

I’m backing two sluggers and have a play on Cleveland Guardians starter Gavin Williams as part of my MLB prop pick recommendations for Wednesday.

Today’s MLB props narrative: Pete Alonso and Max Muncy are on tears and have juicy matchups tonight against a pair of aging arms. I expect them to stay hot.

Check out my favourite MLB prop bets for Aug. 13 to see why I’m fading Williams following the best start of his career.

MLB prop bets

Best bet: Williams under 17.5 outs (-118)

Williams took a no-hitter into the ninth his last time out. He threw a career-high 126 pitches over 8.2 innings, marking the fourth straight start he cleared this outs total. 

That enormous workload gives me pause, and I don’t trust him to clear a number he fails to top more often than not.

On the season, he’s just below a 50% hit rate vs. a 17.5-out line (11-12).

Williams has an impressive 3.17 ERA, a strong whiff rate and excellent velocity. But until he gets his walks under control, I’m not expecting six-plus innings on the regular.

  • The right-hander issued four walks in the near-no-hitter and has walked multiple batters in all but three starts. 
  • His 12.6 BB% is the highest mark among qualified starters and he’s been well above the league-average mark in each of his three seasons. 

The Miami Marlins don’t draw a lot of free passes (21st in MLB), but they’ve been a better-than-league-average offence vs. righties. 

Cleveland’s bullpen worked four innings yesterday but was off Monday, so the group shouldn’t be overly taxed ahead of tonight.

Key stat: Since Williams’ debut in 2023, only three pitchers have a higher walk rate (minimum 250 innings).

Best MLB picks

Alonso over 1.5 total bases (+100): I’m endorsing Alonso as one way to fade Atlanta Braves starter Carlos Carrasco.

The veteran right-hander, making his third start for the Braves, was pummeled his last time out: nine hits and six runs over 5.2 innings.

He has a 6.18 ERA in 10 appearances between the Braves and New York Yankees. Last year, his ERA was 5.64, and the year before that, 6.80.

Atlanta’s bullpen hasn’t been good, either, sporting a 5.88 ERA in the second half (27th in MLB).

Carrasco isn’t fooling anyone at this point in his career and is a good bet to surrender plenty of contact.

A red-hot Alonso is among the Mets who can deliver big contact.

  • The first baseman (.925 OPS vs. RHPs) is batting .350 and slugging .900 this month.
  • His .267 average is the second-best mark of his career and he’s always a big power threat. Alonso has six homers this month and 28 on the season.

Muncy over 1.5 total bases (+110) & 1+ RBI (+125): Like Carrasco, Kyle Hendricks is well past his best-before date.

The righty has pitched much better vs. left-handed batters this year but that hasn’t always been the case, and Muncy is a no-doubter play with a platoon advantage.

Hendricks doesn’t miss bats and doesn’t issue many walks, meaning Dodgers hitters should be challenged in the zone. They’re tied for first in wRC+, and they’ll be at a great hitter’s park, making this a terrible spot for Hendricks at home.

  • Muncy has a .983 OPS vs. righties, blasting 15 of his 17 homers off them.
  • He’s been a beast in August, batting .348 and slugging .870. He has four homers and eight RBI in nine games, hitting behind the Dodgers’ collection of former MVPs.

MLB prop picks made at 3:20 p.m. ET on 08/13/2025.

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Chris joined NorthStar Gaming from Covers.com where he was a publishing editor and wrote betting content. Before that, he was the sports editor at VICE Canada, worked for theScore and covered the Blue Jays for MLB.com. In addition to filling out the lineup card each day for the editorial team, Chris writes frequently himself, primarily on the NBA and MLB.