How and where to bet MLB player prop picks, odds for Aug. 21: Sonny Gray among best bets

Thursday's MLB schedule is almost entirely composed of afternoon games, with only three games beginning after 7 p.m. ET. One of them is the start of a huge Yankees vs. Red Sox series in the Bronx as the longtime rivals scrap for wild card spots. Elsewhere, the Cubs and Brewers wrap up a long series at Wrigley Field, and the Rays welcome the Cardinals to Tampa. With so many games on tap, there are plenty of player props for those interested in MLB betting to get in on at the top sportsbooks.

The SportsLine Projection Model simulates every MLB game 10,000 times. It enters Week 21 of the 2025 MLB season at a profitable 31-23 on top-rated MLB money line picks. The Inside the Lines team has locked in on its most favorable props for Wednesday's games. Here are some of their best plays.

Best MLB player prop pick for Thursday, Aug. 21:

• Sonny Gray Over 5.5 strikeouts

Sportsbook promos for MLB player props on Thursday, Aug. 21

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The Caesars Sportsbook promo code gives new users 20 100% profit boost tokens after placing a wager of at least $1.

Best MLB prop on Thursday

Sonny Gray Over 5.5 strikeouts

Even though we are fading the Cardinals in their road game at Tampa Bay on the money line and run line, the model does like the value on Sonny Gray Over 5.5 Ks. FanDuel is offering the best price at the moment at -136. Gray got hit hard in his last outing, allowing six earned runs, but he still tallied seven strikeouts (7+ in each of his last three starts). Gray has averaged slightly more Ks on the road (6.4) vs. at home (6.1) this season and is 5-4 to the Over on this line. Last season this was a layup when he was 24-4. Other pitchers who average 6.0 to 6.5 Ks per start come in 5-1 to this Over vs. Tampa Bay.

Check out the SportsLine Projection Model's predictions for this game, as well as expert picks.

MLB home runs, stolen bases, strikeouts cheat sheet

The SportsLine Projection Model was developed and is powered by the Inside the Lines team. You can find all of the team's picks and content at our blog, which has all our personal best bets for free. The system is simple. We take the strongest SportsLine Model projected values vs. the best available prices at the time we publish our content. In most cases, lines move in our direction, so you should bookmark the blog, follow us on social, and make it a habit of checking for updates throughout the day to maximize your expected value. 

The table below shows today's projected leading home run, stolen base and strikeout leaders. We include the projection, and for HRs and SBs the money line we'd set for YES HR/SB. You can use this cheat sheet to compare it to your book's line and if your book's line is significantly higher than ours (and you like the player), then you would want to consider that bet.

Check out the model's full slate of projections for today's MLB action.

Shohei Ohtani