The Seattle Mariners have been on the road for nine straight, but on Friday they’ll finally head home. They will open a three-game series against the Chicago Cubs at 10:10 p.m. ET at T-Mobile Park. The oddsmakers see this as too close to call between Seattle at -110 and Chicago at -109.

The Brewers hit the Mariners with a six-run first inning on Thursday, which goes a long way in explaining the final result. The Mariners fell 7-4 to the Brewers.

The Mariners got a good showing from Michael Rucker, who pitched 2.2 innings while giving up no earned runs or hits. Rucker also struck out four batters, his most since April 30, 2022.

At the plate, the Mariners saw five different players step up and record at least one hit. One of them was Brendan Donovan, who went 2-for-4 while logging two RBIs and a double.

Meanwhile, Wednesday was a slow day for the Cubs as the team failed to score. They took a 3-0 hit to the loss column at the hands of the White Sox. The home team had earned the win in each of the previous four meetings, but that streak is no more.

Seattle is now 60-68, having gone 4-3 since its six-game losing streak ended. As for the Cubs, their loss dropped their record down to 74-54.

Seattle took the victory against Chicago in the teams’ previous matchup on June 22, 2025, by a conclusive 14-6 score. Will the Mariners repeat their success, or do the Cubs have a better game plan this time around? We’ll find out soon enough.

How to Watch Chicago Cubs at Seattle Mariners

• Date: August 21, 2026
• Time: 10:10 p.m. ET
• Venue: T-Mobile Park
• TV: Mariners.TV
• Streaming: Stream on Fubo
• Buy tickets: Buy Cubs at Mariners tickets on Ticketmaster

Probable Starting Pitcher Analysis

Emerson Hancock (SEA)

2026 Season Stats: 7-7 | 3.30 ERA | 1.11 WHIP | 8.4 K/9

• Won last start on August 15 @ HOU- 7 IP, 2 ER, 5 H
• 3.30 earned run average this season; 4.90 last season
• Pitching with five days rest
• Last start vs CHC (June 21, 2025, road): (L) 4 IP, 9 ER, 6 H

Matthew Boyd (CHC)

2026 Season Stats: 8-2 | 4.02 ERA | 1.24 WHIP | 7.2 K/9

• Lost last start on August 15 vs. STL- 5.1 IP, 7 ER, 5 H
  • 4 HR allowed – most since August 31, 2019
• 4.8 strikeouts per nine innings in last seven starts; 10.0 strikeouts per nine innings in prior eight games
• High run support: 6.2 per game this season
• Last start vs SEA (June 20, 2025, home): (ND) 5 IP, 2 ER, 2 H

Chicago Cubs vs. Seattle Mariners Betting Odds

• Moneyline: CHC -109 / SEA -110
• Run line: CHC -1.5
• Over/Under: 8

Betting lines as of 08/21/2026 at 8:28 AM ET. Odds subject to change. Bet with bet365.

Chicago Cubs Stat Check: Who’s Hot, Who’s Not

Who’s Hot

• No players currently match our analysis around current trends.

Who’s Not

• Ian Happ (CHC): 0 extra-base hits in nine straight games
  • Previous Game: 0-3, 2 K
• Nico Hoerner (CHC): 0 extra-base hits in seven straight games
  • Previous Game: 0-3
• Michael Busch (CHC): .161/.212/.258 in last eight games; .248/.358/.395 in prior 118 games
  • Previous Game: 0-3

Seattle Mariners Stat Check: Who’s Hot, Who’s Not

Who’s Hot

• Dominic Canzone (SEA): 1+ time on base in 10 straight games
• Brendan Donovan (SEA): 5-10, two RBIs and two doubles in last three games; .254/.348/.385 in prior 35 games

Who’s Not

• Weston Wilson (SEA): .135/.289/.243 since Jul. 22; .231/.306/.400 in prior 28 games

• Jhonny Pereda (SEA): .265/.265/.265 since Jun. 6; .275/.356/.425 in prior 13 games

Last 10 Games for Chicago Cubs (6-4)

• Aug. 19: L vs. CWS 0-3
• Aug. 18: W vs. CWS 4-3
• Aug. 17: W vs. CWS 7-5
• Aug. 16: L vs. STL 4-11
• Aug. 15: L vs. STL 4-8
• Aug. 14: W vs. STL 3-0
• Aug. 13: L @ WSH 0-7
• Aug. 12: W @ WSH 12-6
• Aug. 11: W @ WSH 8-6
• Aug. 9: W @ KC 10-2

Last 10 Games for Seattle Mariners (4-6)

• Aug. 20: L @ MIL 4-7
• Aug. 19: W @ MIL 7-5
• Aug. 18: L @ MIL 0-22
• Aug. 16: W @ HOU 3-2
• Aug. 15: W @ HOU 10-5
• Aug. 14: L @ HOU 7-10
• Aug. 13: W @ NYY 1-0
• Aug. 12: L @ NYY 5-10
• Aug. 11: L @ NYY 1-4
• Aug. 9: L vs. TB 1-4

Final Score Prediction for Chicago Cubs @ Seattle Mariners on August 21, 2026

Cubs 3 – Mariners 4

Lean: Mariners

Give us the Cubs on the run line and the Mariners on the moneyline, as we like Emerson Hancock to build on his last start.

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