American League playoff contenders are set to meet tonight in Seattle. Times have been tough recently for the Mariners, losers in six of their previous seven contests. The same is true for the visiting Guardians, who have now dropped three straight series. On Friday, one of these squads will hope to get back on track with a win in the Emerald City. Below, I’ve laid out my preview, prediction, and best bet for this battle between the Guardians and Mariners.
The Mariners enter tonight as slight favorites (-113) over the Guardians, with the over/under set at seven runs. Let’s break down which side has the edge on DraftKings Sportsbook going into Friday’s contest.
Guardians at Mariners prediction, preview
These two clubs have been built in a similar fashion, prioritizing strong starting pitching and quality fielding. However, Seattle has been surprisingly deadly at the plate, ranking 14th in the league in runs per game (4.34). Unfortunately for the Mariners, that number drops to 4.03 when playing at home. It’s not exactly a shock; T-Mobile Park has earned its reputation as baseball’s most pitcher-friendly venue. Regardless, the M’s still have several standout hitters, including major league home run leader Cal Raleigh at catcher. Right now, six different regulars in Seattle’s lineup have recorded a wRC+ greater than 100 (above average).
The pitcher tasked with slowing down the Mariners tonight will be Gavin Williams. This season, the 25-year-old has notched a 3.86 ERA and 71 strikeouts over 65.1 innings of work. However, Cleveland’s young starter has posted a mediocre WHIP of 1.42, not exactly a recipe for long-term success. Still, Williams has allowed more than three earned runs in only three of his thirteen outings in 2025. This could be a difficult spot for the Mariners, who have posted baseball’s ninth-lowest batting average against righties (.241).
To keep the Guardians in check, Seattle will hand the ball to Luis Castillo. The ninth-year pro is no longer in his prime, but he remains a force to be reckoned with. Over 13 outings this season, the three-time All-Star owns a 3.31 ERA, 1.30 WHIP and 60 strikeouts. Following a stellar month of May, the veteran coughed up six runs in five innings against the Angels last weekend. He’ll look to turn the page tonight against a top-heavy Guardians lineup. Other than Jose Ramirez (160 wRC+) and Steven Kwan (127 wRC+), there aren’t many standouts on offense. So far, Cleveland has scored the seventh-fewest runs per game in baseball (3.96).
Guardians at Mariners pick, best bet
Best Bet: Mariners ML (-113)
Given how inconsistent these offenses have been, the under makes sense in theory. However, seven runs is not a big enough total to feel confident in. Seattle has the better arm on the mound and a deeper lineup. Keeping that in mind, I’ll back the Mariners at near-even money tonight.
