2021 ALDS Predictions | Red Sox vs Rays Best Bets & Projections

Last Updated: Oct 8, 2021

After vanquishing the New York Yankees in the AL Wild Card Game, the Boston Red Sox will face another division rival in the ALDS — the Tampa Bay Rays.

Boston held the best record in the American League for much of the first half before Tampa Bay lapped them down the stretch, finishing with a league-high 100 wins — eight more than the Red Sox. Both teams feature elite offenses, ranking in MLB’s top five in scoring, but the Rays have superior pitching after compiling MLB’s best ERA this season.

Below I’ll go over my model’s probabilities in all potential Boston vs Tampa Bay MLB playoff games before getting into my Red Sox vs Rays predictions and best bets. Please note that all ALDS odds and lines are current as of Thursday, October 7.

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Red Sox vs Rays ALDS Game Projections

Game 1: Boston at Tampa Bay

Eduardo Rodriguez (13-8, 4.74 ERA) vs Shane McClanahan (10-6, 3.43 ERA)

The Red Sox are in a tough spot to start the ALDS after throwing their two best pitchers just to make it here. Chris Sale pitched in the regular-season finale followed by Nathan Eovaldi in the Wild Card Game, leaving Eduardo Rodriguez to start the series opener.

Rodriguez had an up-and-down season after missing all of last year due to COVID complications, but he finished the season strong with a 3.26 ERA and 3.07 FIP from August 1 onward. The lefty also pitched significantly better away from Fenway Park this year with a 3.95 road ERA vs. 5.95 at home.

The Rays will counter with their own southpaw in Shane McClanahan, a 24-year-old rookie who emerged as the most reliable arm in Tampa Bay’s rotation after Tyler Glasnow went down with a season-ending injury. He was extremely consistent for a rookie, never yielding more than four earned runs in a start and allowing three earned runs or less in 22 of his 25 outings.

While the betting markets are more likely to favor the Rays at home, my model gives a slight edge to the Red Sox in Game 1.

Red Sox vs Rays Game 1 Projection (Kevin Davis Model): Red Sox 50.9%

Red Sox vs Rays Game 1 Pick: Red Sox if +105 or better, Rays if +112 or better

Game 2: Boston at Tampa Bay

Chris Sale (5-1, 3.16 ERA) vs Shane Baz (2-0, 2.03 ERA)

After starting Rodriguez in Game 1, the Red Sox will come back with another southpaw in Game 2. Sale missed most of the season while recovering from Tommy John surgery but returned in time to make nine starts down the stretch, helping Boston reach the postseason.

While Sale has pitched effectively this year, he’s yet to recapture his pre-surgery dominance. He’s also averaging fewer than five innings per start, so Alex Cora will likely need to tap into his bullpen early on in Game 2.

Opposing Sale is another Rays rookie, Shane Baz. The 22-year-old former first-round pick is just a few weeks removed from his MLB debut and has only 13 1/3 big-league innings under his belt. While he’s pitched well in his three MLB starts thus far, he’s yet to pitch in a meaningful game as Tampa Bay had already locked up the division by the time he arrived.

Sale and Boston should win Game 2, but it will likely be a sweat as both starters figure to be lifted during the middle innings.

Red Sox vs Rays Game 2 Projection (Kevin Davis Model): Red Sox 52.7%

Red Sox vs Rays Game 2 Pick: Red Sox if -103 or better, Rays if +121 or better

Game 3: Tampa Bay at Boston

Drew Rasmussen (4-1, 2.84 ERA) vs Nathan Eovaldi (11-9, 3.75 ERA)

After dominating the Yankees in the AL Wild Card Game, Eovaldi will return to face his former team in Game 3. Eovaldi has been Boston’s best pitcher all season long and one of the best in the AL this year, leading the league with a 2.79 FIP. His swing-and-miss ability should play well against a Rays offense that posted MLB’s fifth-highest strikeout rate (24.1%) this year.

Opposing Boston’s ace is yet another Rays rookie in Drew Rasmussen, who spent the majority of the season in the bullpen before moving to the rotation in August. Rasmussen was lights-out down the stretch with a 1.46 ERA over his final eight starts, but averaged fewer than five innings per turn and probably won’t stick around for the third time through the order.

Back home at Fenway Park with Eovaldi on the bump, the Red Sox should win Game 3.

Red Sox vs Rays Game 3 Projection (Kevin Davis Model): Red Sox 57.1%

Red Sox vs Rays Game 3 Pick: Red Sox if -123 or better, Rays if +145 or better

Austin Meadows Tampa Bay Rays OF

The defending AL champion Tampa Bay Rays will face a familiar foe in the 2021 ALDS in the Boston Red Sox. (Image: USA TODAY Sports)

Game 4: Tampa Bay at Boston (If Necessary)

Ryan Yarbrough (9-7, 5.11 ERA) vs Tanner Houck (1-5, 3.52 ERA)

Should the series go to Game 4, Boston will be heavily favored to win at home against Ryan Yarbrough, who posted the worst ERA (5.11), FIP (4.45), and strikeout rate (6.8 K/9) of his career in 2021.

Cora will have to choose between Nick Pivetta and rookie Tanner Houck, both of whom have had their moments since making their Red Sox debuts in 2020. Pivetta remained in the rotation for all of this year while Houck shuttled back and forth between Triple-A and the majors, but Houck is better-suited for the postseason given his superior strikeout rate (career 11.3 K/9).

Houck likely won’t pitch past the fifth inning if he starts, but Boston’s bats should do enough damage against Yarbrough to earn the dub.

Red Sox vs Rays Game 4 Projection (Kevin Davis Model): Red Sox 60.7%

Red Sox vs Rays Game 4 Pick: Red Sox if -142 or better, Rays if +168 or better

Game 5: Boston at Tampa Bay (If Necessary)

Chris Sale (5-1, 3.16 ERA) vs Shane McClanahan (10-6, 3.43 ERA)

If there is an epic Game 5 showdown in Tampa Bay, chances are it will be between Sale and McClanahan. Both teams would be quick to empty their bullpens in this winner-take-all game, however, so it’s difficult to forecast how it will play out.

Personally, I have no idea what to expect. Sale has been inconsistent lately, so he could dominate or be yanked early. McClanahan has been more steady, but he could also be overwhelmed by the pressure of the moment.

While I have factored the toss-up nature of Game 5 into my model, chances are I won’t be betting on this game unless my model sees a big enough edge due to all the uncertain tactics in such a consequential game.

Red Sox vs Rays Game 5 Projection (Kevin Davis Model): Red Sox 50.7%

Red Sox vs Rays Game 5 Pick: Red Sox if +105 or better, Rays if +111 or better

Red Sox vs Rays ALDS Futures Bets

Red Sox vs Rays ALDS Winner Bets

Best Bet: Boston Red Sox ALDS Series Winner (+160) at BetRivers (would bet up to +100)

Wager: 2 Units

It’s usually a bad sign if your model is way off from the betting market, which is typically efficient in the long run. After double-checking my numbers, however, the Red Sox appear undervalued in this series based on our MLB gameday odds.

With two strong lineups, this series will ultimately come down to pitching. Tampa Bay will be relying on rookies in four out of five starts and their worst starter (Yarbrough) in the fifth. Meanwhile, Eovaldi, Sale, and Rodriguez are all veteran hurlers with postseason experience from Boston’s 2018 title run.

While the Rays have found unique ways to win over the years, like the Oakland A’s they haven’t figured out a way to convert all their regular-season success into a championship. The Red Sox have, however, and shouldn’t be discounted. They are capable of dominating as they did during the first half and are being overlooked, which is why I’m hammering them against the Rays for my MLB bet of the day.

Kevin Davis Series Winner Model Projection: Red Sox 58.3%

Red Sox vs Rays ALDS Winner Pick: Red Sox if -120 or better, Rays if +150 or better

Red Sox vs Rays ALDS Exact Score Bets

Best Bet: Boston Red Sox 3-0 Series Winner (+1000) at BetRivers (would bet up to +700)

Wager: 1 Unit

Best Bet: Boston Red Sox 3-1 Series Winner (+450) at BetRivers (would bet up to +350)

Wager: 0.5 Units

Without boring you with the math, let me explain how my model calculated the odds of each exact series score.

To figure out the chances of the exact series score, I simulated each potential ALDS game 100,000 times. After my simulations in Microsoft Excel, I counted the number of times that each series ended in a specific score.

Unsurprisingly, I like Boston exact score markets as my model expects them to win the series. What was surprising to me is that my model likes the Red Sox to sweep at +1000.

At 9.1% breakeven odds, this is a good bet as Boston sweeps Tampa Bay in 15.3% of my simulations. If the Red Sox can win the first two games at the Trop, they could easily finish the job in Game 3 with Eovaldi on the mound at Fenway.

If Boston splits the first two games on the road and then wins Game 3, they should also win Game 4 at home against Yarbrough. That is why my second favorite series exact score bet is for the Red Sox to win the ALDS 3-1 at +450.

Red Sox vs Rays ALDS Predictions (Kevin Davis Model; Breakeven Odds in Parentheses):

  • Red Sox 3-0: 15.3% (+554)
  • Red Sox 3-1: 24.2% (+313)
  • Red Sox 3-2: 18.8% (+432)
  • Rays 3-0: 9.9% (+911)
  • Rays 3-1: 13.5% (+639)
  • Rays 3-2: 18.3% (+446)

Thanks for reading our Red Sox vs Rays ALDS Predictions! For more MLB betting tips, check out our 2021 World Series Champion Predictions.


Kevin Davis

Kevin Davis is a Betting Analyst at The Game Day residing in Hoboken, NJ. Previously a Bronx resident, Kevin got his start betting on sports at his local Bronx barbershop. When sports betting was legalized across the river in Jersey, Kevin was there on the ground floor making regular trips to the Hoboken PATH station or for soup dumplings in Fort Lee. Previously, Kevin has written for The Action Network, and Vegas Insider.

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