San Francisco Giants vs Seattle Mariners Prediction 7/18/2026 Today’s MLB Picks

In this article, we will formulate a Giants vs Mariners Prediction for this MLB matchup on Saturday, July 18th in the second game of this series. Let’s take a look at the prediction for this MLB matchup.

Seattle Mariners Preview

The Seattle Mariners have a 48-50 record this season and are sitting in the 2nd place of the AL West. They have a 27-21 home record and are coming off a 0-7 home loss against the Giants. They will face the Reds and the Rangers next.

The Seattle Mariners have a .228 batting average this season, .309 OBP and .377 Slugging percentage. Seattle’s pitching staff has a 3.64 ERA and 1.19 WHIP. Randy Arozarena is the team’s best hitter with a .283 batting average and also leads the team in RBI with 45, while Dominic Canzone adds a team-high 15 home runs.

Bryan Woo (R) is the projected starting pitcher for the Seattle Mariners, and he has a 7-6 record, 4.23 ERA and 1.07 WHIP.

San Francisco Giants Preview

The San Francisco Giants have a 42-55 record this season and are sitting in the 4th place of the NL West. They have a 20-30 away record and are coming off a 7-0 road win against the Mariners. They will face the Royals and the Angels next.

The San Francisco Giants have a .256 batting average this season, .310 OBP and .420 Slugging percentage. San Francisco’s pitching staff has a 4.42 ERA and 1.36 WHIP. Luis Arraez is the team’s best hitter with a .328 batting average. Rafael Devers leads the team in RBI with 52, adding a team-high 19 home runs.

Logan Webb (R) is the projected starting pitcher for the San Francisco Giants, and he has a 5-7 record, 3.86 ERA and 1.16 WHIP.

San Francisco Giants @ Seattle Mariners Betting Trends: July 18, 2026

• Probable Starting Pitcher: Bryan Woo      Record this season: 7-6      ERA: 4.23
• Home Record: 6-0
• Last 5 against Giants: 1-0

Why the Seattle Mariners will win

• The Mariners have won each of their last seven games against the Giants at T-Mobile Park following a loss.
• The Giants have lost six of their last seven night games following a road win.
• The Mariners have covered the run line in each of their last five games as home favorites after playing the previous day.
• The Giants have failed to cover the run line in three of their last four games against American League opponents after playing the previous day.
• The Mariners have led after 3 innings in five of their last six night games against National League opponents that held a losing record.
• The Mariners have led after 5 innings in three of their last four games against NL West opponents.

• Probable Starting Pitcher: Logan Webb      Record this season: 5-7      ERA: 3.86
• Road Record: 3-3
• Last 5 against Mariners: 0-1

Why the San Francisco Giants will win

• The Mariners have lost each of their last four games as favorites against National League opponents.
• The Giants have won each of their last four games as underdogs against AL West opponents.
• The underdogs have covered the run line in each of the Giants’ last 10 games at T-Mobile Park.
• The Mariners have failed to cover the run line in each of their last seven games as favorites against NL West opponents following a loss.
• The Mariners have trailed after 5 innings in each of their last nine games against National League opponents.
• The Giants have won the first inning in three of their last four games at T-Mobile Park.
• The Mariners have trailed after 3 innings in five of their last six night games.

Total Runs Facts

• Five of the Giants’ last six games as underdogs have gone OVER the total runs line.
• Three of the Mariners’ last four games after playing the previous day have gone OVER the total runs line.
• There has been no run scored during the first inning in each of the Mariners’ last 12 games.
• There has been no run scored during the first inning in seven of the Giants’ last eight night games at T-Mobile Park.

Seattle Mariners Player Prop Facts

• Dominic Canzone has hit a home run in three of his last four home appearances after playing the previous day.
• Bryan Woo has recorded a win in each of his last eight home appearances against NL opponents.
• Bryan Woo has recorded six or more strikeouts in each of his eight previous appearances with the Mariners as home favorites against NL opponents.
• Josh Naylor has recorded at least one hit in each of his last 14 appearances in night games against NL West teams that held a losing record.
• Bryan Woo is one of only three pitchers to record 90+ Strikeouts and 20 or less Walks this season.

San Francisco Giants Player Prop Facts

• Willy Adames has hit a home run in each of the Giants’ last two games against AL West opponents.
• Logan Webb has recorded a win in each of his last four appearances against AL West opponents that held a losing record.
• Logan Webb has recorded six or more strikeouts in eight of his last nine appearances in night games against AL teams that held a losing record.
• Luis Arraez has recorded at least one hit in each of his last 18 appearances in night games against AL teams that held a losing record.
• Luis Arraez ranks 2nd in the league in Hits (120) this season.

Matchup/League Facts

• The Mariners rank 1st in the league for walks allowed this season (244).
• The Mariners rank 1st in the league for home runs allowed this season (92).
• The Giants rank 30th in the league for walks this season (242).
• The Giants rank 3rd in the league for doubles this season (179).

Giants vs Mariners Prediction

The Giants have won their last four meetings against the Mariners and two of their last three visits in Seattle.  

In this Giants vs Mariners Prediction, the Mariners are coming as -135 home favorites. The Mariners have been struggling mightily with a 1-6 record in their last 7 games and were shut out yesterday, but I like them in a bounce-back spot today with Bryan Woo on the mound, who has been elite at home with a 6-0 record and a 2.10 ERA. On the flip side, Logan Webb has given up 12 runs in his last two starts and I don’t trust him on the road. Take the Mariners to win this one at home.

Nikos Lagouretos's Pick: Seattle Mariners ML