Seattle Mariners vs Chicago Cubs Prediction – 6/20/2025

On June 20, 2025, the Chicago Cubs will host the Seattle Mariners at Wrigley Field for the first game of their interleague series. The Cubs, sitting at 45-29, are enjoying a strong season, while the Mariners are hovering around .500 with a record of 37-36.

Matthew Boyd, projected to start for the Cubs, has been solid this season with a Win/Loss record of 6-3 and an impressive ERA of 2.79. However, his xFIP of 3.98 suggests he may have been a bit lucky and could face challenges going forward. Boyd's low walk rate (5.8 BB%) will be crucial against the Mariners, who rank 6th in walks drawn.

On the other side, George Kirby takes the mound for Seattle. Despite being ranked 30th in MLB starting pitcher Power Rankings, his ERA of 5.96 indicates struggles this season. Kirby's projections show he may allow 3.2 earned runs and 6.2 hits today, adding to concerns about his performance.

The Cubs’ offense has been explosive this season, ranking in the top 5 for home runs and demonstrating their ability to capitalize on pitching mistakes. With a Game Total set at 9.5 runs, the Cubs have a strong implied team total of 4.97 runs, suggesting that oddsmakers expect them to capitalize on Kirby's struggles. Meanwhile, the Mariners' offense, while good for home runs, ranks only 14th overall, hinting at potential difficulties against a solid Cubs pitching staff.

Quick Takes Seattle Mariners:

Despite conventional wisdom, fastballs are typically a pitcher's least effective pitch. George Kirby has relied on his fastball a lot this year, though: 56.6% of the time, ranking in the 100th percentile.

• Fastballs are the one easiest pitches to hit and generate few strikeouts, so pitchers who rely too heavily on them tend to be less effective than they otherwise would be.

Cal Raleigh is an extreme flyball hitter and faces the strong outfield defense of Chicago (#2-best on the slate today).

• This player's skill set matches up poorly with the opposing team's defensive strength, which may lead to worse-than-usual performance.

Cal Raleigh pulls many of his flyballs (43% — 100th percentile) and is a great match for the park considering he'll be hitting them towards MLB's 6th-shallowest LF fences today.

• This player's skill set matches up particularly well with the park he's in today, which may lead to better-than-usual performance.

Quick Takes Chicago Cubs:

The Chicago Cubs infield defense profiles as the 2nd-strongest out of every team today.

• Defense is an integral part of preventing hits and runs.

Michael Busch is projected to bat 6th in the batting order in this matchup, which would be a downgrade from his 74% rate of hitting in the top-half of the lineup this season.

• The lower in the order a player bats, the fewer plate appearances he will get and the fewer opportunities he will get to hit the Over for every market. A player who hits lower in the order than he normally does may provide extra value opportunity since the market may be based on him hitting higher.

It may be smart to expect negative regression for the Chicago Cubs offense going forward, considering that the leading projection system (THE BAT X) believes they are the 3rd-luckiest offense in baseball this year.

• When teams overperform their projected talent level, markets may overvalue them even while they are likely to perform worse in the near future.

Game Trends

• The Chicago Cubs have hit the 1st Five Innings (F5) Moneyline in 34 of their last 68 games (+9.65 Units / 9% ROI)
• The Seattle Mariners have hit the 1st Five Innings (F5) Team Total Over in 38 of their last 67 games (+6.40 Units / 8% ROI)
• Dylan Moore has hit the Runs Under in 13 of his last 15 games (+9.00 Units / 31% ROI)

Seattle Mariners vs Chicago Cubs Prediction

Predicted Final Score: Seattle Mariners 5.23, Chicago Cubs 5.27

• Date: June 20, 2025
• Venue: Wrigley Field
• Starting Pitchers:
  • George Kirby - Mariners
  • Matthew Boyd - Cubs

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