Looking for the best MLB prop bets today? We’ve got a few strong spots to target on the April 21 slate, with a mix of offensive upside and pitchers in tough matchups. The Diamondbacks are in a great position against a White Sox staff that has struggled to limit damage, Jo Adell draws a favorable split against Patrick Corbin, and Luis Castillo continues to show signs of regression against a lineup that handles his pitch mix well. Let’s break down the best MLB prop bets on the board.
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Best MLB Prop Bets Today (April 21, 2026)
- Best Team Total: Diamondbacks team total over 4.5: Sean Burke’s struggles and a poor White Sox bullpen has me on the over
- Best Batter Prop: Jo Adell 2+ total bases: Strong matchup vs. LHP Patrick Corbin
- Best Pitcher Prop: Luis Castillo under 17.5 outs recorded: Castillo hasn’t reached six innings in three straight starts and faces a good four-seam hitting club in Athletics
Let’s break down why these stand out on today’s slate.
MLB Prop Bets Breakdown (April 21, 2026)
Let’s break down the top MLB prop bets and picks for today. Click on each headline below to view the latest odds and bet these plays on DraftKings Sportsbook.
Arizona Diamondbacks team total over 4.5 runs (-125) vs. Chicago White Sox
The Diamondbacks’ offense has been rolling lately, averaging 5.6 runs over the past five games. They have a good chance of keeping that going tonight, as they face Sean Burke and the White Sox bullpen. Burke has a 4.43 ERA with an xERA of 4.63 through 20.1 innings. He throws a ton of four-seam fastballs, doing so 42% of the time this season. The Diamondbacks are excellent against that pitch and, dating back to last season, have a combined .365 wOBA with a .232 ISO against it. Throughout his career, Burke has posted poor numbers against lefties, with a career .331 wOBA and a 4.79 FIP against them. The Diamondbacks can load up on lefties and will likely have five in their lineup.
The White Sox bullpen will also provide opportunities for the D-Backs to score some runs. Over the past week, they’ve combined for a 6.43 ERA, a 4.65 FIP, and a 6.4 BB/9. If the D-Backs continue to swing as they have lately, I think they can plate at least five tonight.
Jo Adell 2+ total bases (-105) vs. Toronto Blue Jays
I like this spot for Adell tonight against Patrick Corbin and the Blue Jays. Corbin allowed only one run in his last start against the Brewers, but his xERA of 4.04 suggests it should have been worse. Overall, his xERA of 7.92 through two starts is a perfect representation of who Corbin is. I like this spot for Adell, who has already been a monster against lefties. It’s early, but he sports a .502 wOBA with a .333 ISO and all three of his home runs against them. If you want to pull the data back and include last season, Adell has a .418 wOBA with a .314 ISO and 10 home runs against lefties. With Corbin using his cutter and sinker more, this sets up very well for Adell.
Luis Castillo under 17.5 outs recorded (-102) vs. Athletics
Castillo has not looked like himself in the early stages of 2026. He’s been as bad as his stats indicate, with a 5.40 ERA, an xERA of 5.60, and a 44% hard-hit rate. Opposing hitters have a minimum .388 wOBA against all of his pitches this season, including a .424 wOBA against his slider. He’ll face an Athletics lineup that hits four-seam fastballs well, as they’ve combined for a .351 wOBA and a .164 ISO against that pitch this season.
Castillo has only pitched six innings in one of his four starts, which was his first start of the season against the Yankees. Since then, he’s gone no more than 5.1 innings against the Angels, Astros, and most recently, the Padres.
More MLB Betting Content & Picks
Check out more MLB betting content and player props throughout the season on DraftKings Network.
- MLB NRFI Tracker
- MLB Best Bets: Top NRFI props for Tuesday 4/21/26
- MLB Probable Pitchers for April 21, 2026
Good luck with your MLB prop bets today!
