Boston Red Sox vs San Francisco Giants Pick – 6/21/2025

As the San Francisco Giants prepare to host the Boston Red Sox on June 21, 2025, both teams find themselves in the middle of a competitive season. The Giants hold a record of 42-34, showcasing a solid performance, while the Red Sox sit at 40-37, reflecting an average campaign. This matchup is particularly intriguing given that it’s the second game in their interleague series, with the Red Sox winning the first game on Friday.

On the mound, the Giants project to start Landen Roupp, who has had an inconsistent year with a 4-5 record and a 3.99 ERA. Roupp's average projection of 5.3 innings pitched and 2.2 earned runs allowed indicates he may be in for a decent outing. However, he faces a challenge against a Red Sox offense that ranks 8th in MLB, known for its ability to generate runs and power with 8th best in home runs.

Brayan Bello, projected to start for the Red Sox, comes into this game with a more impressive 3-1 record and a stellar 3.49 ERA. However, Bello's elevated xFIP of 4.31 suggests he may have benefited from some good fortune this season, which could spell trouble for him moving forward. The Giants' offense, while struggling overall (ranking 22nd in MLB), boasts a patient approach, ranking 3rd in walks drawn. This could play to their advantage against Bello, who has a high walk rate of 10.8%.

With the Giants' bullpen ranked 1st in MLB, they have a significant edge if the game remains close. Betting markets currently favor the Giants with a moneyline of -135, suggesting a tight game ahead. Overall, the matchup presents an opportunity for the Giants to capitalize on their home-field advantage and the Red Sox's potential vulnerabilities.

Quick Takes Boston Red Sox:

Brayan Bello's higher utilization rate of his fastball this year (51.9 vs. 45% last year) is not ideal since they are generally much less effective than breaking or off-speed pitches.

• Fastballs are the one easiest pitches to hit and generate few strikeouts, so a pitcher who begins to use his fastball more often will likely be less effective than he used to be.

Marcelo Mayer has seen a sizeable improvement in his exit velocity lately; just compare his 99.4-mph average in the past week to his seasonal 92.6-mph average.

• Hitting the ball hard increases the chances of either a home run or the ball landing in fair territory for a hit before a fielder can get to it.

Today’s version of the Red Sox projected batting order is missing some of their usual firepower, as their .311 the leading projection system (THE BAT X) wOBA is considerably below their .322 overall projected rate.

• Betting lines are often based on seasonal team quality. If today's lineup is watered down, however, there may be value if markets aren't accounting for the lower quality of this offense.

Quick Takes San Francisco Giants:

The San Francisco Giants infield defense profiles as the 2nd-weakest among all the teams today.

• Defense is an integral part of preventing (or, in this case, allowing) hits and runs.

Extreme flyball batters like Mike Yastrzemski generally hit better against extreme groundball pitchers like Brayan Bello.

• This mostly has to do with the way the hitter's swing plane interacts with the pitch trajectory, and it can create boosted performance across all categories and hidden value few are considering.

The San Francisco Giants bullpen grades out as the best in MLB, via the leading projection system (THE BAT).

• Most bettors only consider the starting pitcher, but a strong bullpen sneakily creates a tougher matchup for the opposing offense and suppresses a game's runs.

Game Trends

• The San Francisco Giants have hit the Game Total Under in 34 of their last 58 games (+10.25 Units / 16% ROI)
• The Boston Red Sox have hit the Moneyline in 9 of their last 11 games (+9.60 Units / 80% ROI)
• Marcelo Mayer has hit the Singles Under in 9 of his last 10 games (+7.30 Units / 43% ROI)

Boston Red Sox vs San Francisco Giants Prediction

Predicted Final Score: Boston Red Sox 3.96, San Francisco Giants 4.19

• Date: June 21, 2025
• Venue: Oracle Park
• Starting Pitchers:
  • Brayan Bello - Red Sox
  • Landen Roupp - Giants

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