Seattle Mariners at Boston Red Sox odds, picks and predictions


The Seattle Mariners (17-21) head to Fenway Park Thursday to start a 4-game series with the Boston Red Sox (15-22) at 7:10 p.m. ET. Let’s analyze Tipico Sportsbook‘s lines around the Mariners vs. Red Sox odds with MLB picks and predictions.

Seattle prevented a 3-game sweep at the Toronto Blue Jays with a 5-1 win Wednesday and is 5-5 overall in its last 10 games.

Boston is also 5-5 overall in its last 10 but won 2 of 3 in the previous series vs. the Houston Astros.

Mariners at Red Sox projected starters

RHP George Kirby vs. LHP Rich Hill 

Kirby is 0-0 with a 0.90 ERA (10 IP, 1 ER), 7 H, 1 BB and 8 K over 2 starts in his rookie season.

  • His first outing was a quality start in Seattle’s 2-1 win over the Tampa Bay Rays May 8 with 6-scoreless IP. He then gave up 1 ER over 4 IP in his second start at the New York Mets in a 5-4 loss Saturday.

Hill is 1-1 with a 2.89 ERA, 1.11 WHIP, 2.3 BB/9 and 6.8 K/9 through 28 IP over 6 starts.

  • Last start: Win, 11-3, Saturday at the Texas Rangers with 6 IP, 2 ER (3 R), 7 H, 0 BB and 4 K.
  • vs. Mariners on the current roster: 5.16 FIP with a .273/.352/.526 expected batting average, wOBA, slugging percentage slash line, 34.6 K% and 85.0 mph exit velocity in 52 plate appearances.

Mariners at Red Sox odds and lines

  • Money line (ML): Mariners +102 (bet $100 to win $102) | Red Sox -125 (bet $125 to win $100)
  • Run line (RL)/Against the spread (ATS): Mariners +1.5 (-200) | Red Sox -1.5 (+160)
  • Over/Under (O/U): 8.5 (O: -110 | U: -110)

Mariners at Red Sox picks and predictions


Mariners 6, Red Sox 4

Money line

BET the MARINERS (+102) because their 2-8 overall record vs. left-handed starters is misleading and there’s a line freeze in the betting market.

Seattle’s lineup is near or above-average in several advanced hitting metrics against lefty pitching such as wRC+, wOBA, hard-hit rate and BB/K but is being held back by the second-worst BABIP in the MLB at .239. Essentially, the Mariners have had bad luck at the plate vs. lefties and that should normalize.

Nearly 80% of the cash is on the Red Sox according to, but the line hasn’t budged, which is very suspicious. Oddsmakers will typically move the line towards the more popular team but it seems as if the sportsbooks want more pro-Boston action here.

BET 1 unit on the MARINERS (+102).

Run line/Against the spread

PASS because the Mariners +1.5 (-200) is out of my price range and I’m not confident enough in Seattle to sprinkle on its alternate RL.


Slight LEAN to the OVER 8.5 (-110) because Fenway Park isn’t friendly for left-handed pitchers and the Over cashed in 6 of the 7 Mariners-Red Sox meetings in 2021.

But, Seattle is 7-13 O/U as a road underdog with a minus-1.2 total margin and Boston is 4-6 O/U as a home favorite.

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