Chicago Cubs vs Seattle Mariners Prediction, 8/21/2026 MLB Picks, Best Bets & Odds

Game: Chicago Cubs vs Seattle Mariners

Date: Friday, August 21, 2026

Location: T-Mobile Park in Seattle, WA

TV: MLB.TV

Odds/Point Spread: Chicago (-150) Seattle (+125)

T-Mobile Park is the site where the Seattle Mariners (60-67) will try to defeat the Chicago Cubs (74-54) on Friday. The moneyline on this contest has the Cubs at -150 and the Mariners are coming in at +125. The over/under is set at 9. The starting pitchers are Matthew Boyd and Emerson Hancock.

As a team, the Chicago Cubs are scoring 5.1 runs per game, which has them sitting at 2nd in MLB. They have tallied 656 runs and have an on-base percentage of .337. The Cubs have hit 213 doubles as a team and have smacked 164 balls out of the park. They have amassed 617 RBI's as well as 1,089 hits for the year, and their average at the plate is at .248. Chicago owns a slugging percentage of .418 and have been called out on strikes 1,100 times, while being walked on 544 occasions.

Get all of our MLB Parlay Picks

The Cubs have compiled a team earned run average of 4.14 for the season (17th in the league), and their staff has rung up 982 batters. Cubs pitchers have conceded 192 home runs in addition to 556 total runs (13th in the league). Their pitching staff has walked 385 opposing hitters and their FIP is 4.69 as a unit for the year. Chicago has yielded 1,057 hits (8.3 per 9 innings) in addition to 527 earned runs. They have earned a strikeout to walk ratio of 2.55 and their pitching staff has earned a collective WHIP of 1.26.

The Cubs have dispatched 412 relief pitchers to the mound for the year. The relief pitchers have inherited 178 runners on the season with 30.9% of them ended up scoring. The relievers have accumulated 47 holds for the season (30th in MLB). Cubs bullpen pitchers have entered the game with runners on 129 times as well as having 123 appearances in high leverage situations. They have accumulated 29 saves for the year and have blown 20 of 49 save opportunities. The Cubs relief pitchers have earned a save rate of 59.2% and have stepped onto the mound in 102 save situations.

The Chicago Cubs have amassed 3,434 putouts on the campaign, as well as 1,203 assists and 47 errors. Their fielding percentage sits at .990 which has them ranked 1st in professional baseball, and have earned 100 double plays. The Cubs have converted 72.0% of balls hit into play into outs out of 10,302 innings, which has them sitting at 2nd in pro baseball.

Boyd has taken the mound for 1,173 innings and has accumulated 1,113 punch outs in his career. His ERA is 4.53 (591 ER's allowed) and his career WHIP is 1.274. He has conceded 1,132 base knocks (8.7 hits per 9 innings) with 362 walks. Boyd (68-79 win-loss mark in his career) holds a FIP of 4.47 while facing 4,968 batters during his time in the major leagues.

The Seattle Mariners have accounted for an OBP of .310 as well as a team batting average of .230 for the season. They have struck out on 1,090 occasions (9th in baseball) and have accounted for 966 base knocks. Seattle has tallied 145 long balls for the year as well as 480 runs batted in. The Mariners hold a team slugging percentage of .377 and they score 3.91 runs per game (30th in the league). They have recorded 155 two-baggers, while taking a walk 422 times as well as putting up 496 runs.

The Mariners have a WHIP of 1.224 in addition to having a FIP of 3.82 as a staff on the season. They rank 17th in MLB as a staff in total hits given up with 1,049. The Seattle pitching staff have allowed 539 runs so far this year while having an ERA of 3.97 (495 earned runs surrendered). Their strikeout to walk ratio comes in at 8.60 (1,076 strikeouts vs 323 bases on balls). They have conceded 142 homers and they yield 4.33 runs per 9 innings (10th in the league).

Seattle bullpen pitchers hold an inherited score percentage of 30.4% of 125 inherited runners. Their relief pitchers have taken the field 132 times in high leverage situations and on 89 occasions with runners on base. Sitting with 117 save situations, the Mariners have 67 holds and 20 blown saves. They sit at 22nd in the league with a save rate of 59.2%, and they have sent 383 relievers to the hill so far this year.

The Seattle Mariners have gotten 103 double plays and have notched a fielding percentage of .985 (17th in professional baseball). The Mariners have accrued 1,034 assists, 66 errors and have a total of 3,363 putouts on the season. In 10,089 innings played, the Mariners have earned a defensive efficiency of 69.3% (24th in baseball).

During his pro baseball career, Hancock has surrendered 278 base knocks while earning 228 K's in 290 innings pitched. Hancock (15-16 career mark) has earned a 4.16 ERA while conceding 8.6 hits per 9 innings. He has given up a total of 134 earned runs while holding a WHIP of 1.251 and a FIP of 4.1. He has a K/BB ratio of 2.68 and he has faced 1,216 opposing batters so far in his MLB career.

Who will win tonight's MLB game against the spread or moneyline?

Josh Schonwald's Pick: Take Chicago (-150)

Get $60 worth of FREE premium member picks. No Obligation. No Salesman. No Credit Card. Fast Sign up with Instant Access Click Here

Get MLB picks on every single game, or if you want our very best bets by the experts, sign up for your free $60 account with a guarantee.