Mariners Probable Starters and Pitching Matchups vs. Reds, July 20–22

Seattle looks to build on a series win while the Reds arrive searching for answers.

Jul 8, 2026; Miami, Florida, USA; Seattle Mariners starting pitcher George Kirby (68) throws during the first inning against the Miami Marlins at loanDepot Park. Mandatory Credit: Jim Rassol-Imagn Images | USA TODAY Network via Reuters Connect

The Mariners opened the second half of the 2026 season by taking care of business. They won two out three against the San Francisco Giants at home, survived another clunky offensive weekend and reached the 100-game mark with a 50-50 record. It's not where they expected to be, but it keeps them planted in the middle of the AL playoff race with the trade deadline approaching.

In typical Mariners fashion, the biggest takeaway from the series is that we still have no idea which direction this team is heading. Now the Cincinnati Reds have come to town, a team that started the season 20-11 and are watching their own promising season unravel. They enter this set eight games under .500 at 45-53.

There were encouraging signs against San Francisco. Cole Young homered twice during the series, including a game-tying shot in the opener. Julio Rodríguez delivered a walk-off sacrifice fly in extra innings, while Luke Raley went deep in the finale. Logan Gilbert also struck out 10 batters across six innings on July 19.

It wasn’t a perfect series. It was, however, nice to see Seattle take the series win. The Reds arrive with plenty of connections. Luis Castillo will face his former organization again on Tuesday, while the 2022 blockbuster that sent him to Seattle remains one of the defining trades for both franchises. It’s been four years since, so there’s no reason to spend the next three days relitigating that trade. But it would be nice if Castillo pitches like the frontline starter they acquired.

Seattle also has to deal with one of baseball’s most exciting young arms in Chase Burns. Cincinnati recently committed to Burns with a seven-year, $105 million extension, and his performance has already justified the hype. The Mariners will see him Tuesday in what is easily the most intriguing matchup of the series.

Mariners Probable Starters vs. Reds

Monday, July 20, 6:40 p.m. PT: RHP George Kirby (7-8, 3.76 ERA) vs. LHP Andrew Abbott (5-5, 4.11 ERA)

Tuesday, July 21, 6:40 p.m. PT: RHP Luis Castillo (3-8, 4.93 ERA) vs. RHP Chase Burns (11-1, 2.54 ERA)

Wednesday, July 22, 12:40 p.m. PT: RHP Emerson Hancock (6-4, 3.17 ERA) vs. RHP Brady Singer (4-9, 4.56 ERA)

Seattle remains in playoff position because its pitching has kept the floor from collapsing. That formula can still work, but the offense has to begin carrying some of the weight.

Winning two of three against the Giants was a useful start. Taking another series from the Reds would give the Mariners something resembling momentum.