MLB Strikeout Props Picks: Aaron Nola, Luis Castillo Among to Go Over on Monday is an independent sports news and information service. has partnerships with some of the top legal and licensed sportsbook companies in the US. Gaming Today may receive referral compensation from the sportsbook company when you claim a bonus offer or promotion through a link on this site. Although the relationships we have with sportsbook companies may influence the order in which we place companies on the site, all reviews, recommendations, and opinions are wholly our own. They are the recommendations from our authors and contributors who are avid sports fans themselves.

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We’re starting the week in baseball by picking household names on betting lines with value. Our MLB strikeout props for Monday, Aug. 21 include two strikeout leaders going Over their totals, and one up-and-comer on a perennial contender staying Under. Keep reading to check out the even-money or better wagers we’re suggesting for tonight. 

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Today’s Betting Lines

Here are odds from the top sports betting apps for the games we provide our MLB strikeout props from on Monday. For lines on Monday’s entire schedule, check out our MLB odds page. Also, check out the best sports betting promos on the market. 

MLB Strikeout Props (8/20/23)

Here are MLB strikeout props for Monday, Aug. 21.

Christian Javier Under 5.5 Strikeouts (+100 on FanDuel)

The bulk of the Astros pitching staff is having problems, and Christian Javier is included. Javier has taken the mound three times in August and hasn’t tossed five strikeouts in any of those games. His ERA so far this month sits at 5.65. Tonight, he takes the mound against the Boston Red Sox, who are top 10 at avoiding strikeouts and top three in team batting average.

Piling strikeouts against a lineup like the Red Sox doesn’t seem likely given Javier’s slump. That’s especially so given that neither of Javier’s backup pitches is doing well at keeping hitters from tracking his four-seamer. Both his slider and curveball draw chase and strike percentages below league average. That keeps a lot of pressure on his four-seamer to get the job done. As unique as it is thanks to how much it climbs, it’s still on the lower end when it comes to speed. 

Only one of the Red Sox’s 12 hitters with 150 or more plate appearances hit fastballs below .240 this season. That’s a big reason why we’re taking the Under in this spot. 

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Aaron Nola Over 6.5 Strikeouts (+110 on Caesars)

Aaron Nola is picking up where he left in July in the earned runs category. In three starts for the Phillies this month, he has allowed 10 runs and three home runs. He has thrown 100 or more pitches in two games in August and didn’t make it to the sixth inning. However, he has also picked up where he left off in the strikeout category. 

The Phillies' Aaron Nola going Over is one of our MLB strikeout props picks for Monday, Aug. 21, 2023.
Philadelphia Phillies’ Aaron Nola (AP Photo/Matt Slocum)

In his last three starts, he has compiled 21 strikeouts and at least six in each contest. Tonight, he is up against the San Francisco Giants, who are third worse in the category. Over the course of his career, Nola has faced six of the Giants’ current hitters for a total of 97 plate appearances. In those matchups, he is limiting them to a .216 batting average and tossed 34 strikeouts. The batters he faced include J.D. Davis and Joc Pederson, both of whom he has favorable stats against. 

This is also the ideal matchup for Nola to go Over his listed total thanks to his curveball. It is one of the best in the show, drawing a chase percentage nearly 20 percentage points above league average and a strike percentage nearly 10 points above league average. Half of San Francisco’s 12 hitters with more than 150 at-bats hold a batting average of .200 or below against the curveball in 2023. Given how many of them significantly struggle against his best pitch, we like his odds on this line tonight. 

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Luis Castillo Over 6.5 Strikeouts (+108 on FanDuel)

The Mariners are red-hot and closing ground on the Astros, who they just swept on Sunday. Next up on the mound for Seattle is Luis Castillo, who takes the ball against the White Sox. Castillo tossed at least six Ks in six of his last nine games, including a seven-and eight-strikeout performance against the Diamondbacks and Orioles, respectively, in that time span. 

The White Sox, although not as bad as of late, are still one of the worst in the league in the strikeout category, just 11 away from ninth in MLB. As a team, Chicago has a chase percentage about five percentage points above league average. That’s going to cause problems against Castillo. His slider draws a chase percentage four percentage points above average and a strike percentage three points above average. His most used pitch is the four-seamer, which draws a chase percentage four points above average, a strike percentage three points above average, and it holds hitters to a batting average of .159.

That’s a critical statistic because eight of the 11 White Sox hitters with at least 150 plate appearances significantly struggle to hit the slider. This matchup is leaning in Castillo’s favor on paper, and we believe the plus-money odds provide the value worth the risk on this line. 

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About the Author
David Fletcher

David Fletcher

David Fletcher is a sports betting writer at Gaming Today. He has a bachelor’s degree in journalism from Stephen F. Austin State University and has nearly a decade of experience covering high school, collegiate, and professional sports in Houston. Fletcher is a big fan of the Astros, Rockets, and, unfortunately, according to him, the Texans. He enjoys bringing his love of sports and writing to the gaming industry, providing insight into quality sports bets.

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