Nationals vs. Mariners Prediction, Odds, Probable Pitchers and Prop Bets for Tuesday, May 27

Iain MacMillan | May 27, 2025

The Nationals are road underdogs against the Mariners on Tuesday night. / Brett Davis-Imagn Images

Tuesday's MLB action will wrap up on Tuesday night in an interleague showdown between the Washington Nationals and Seattle Mariners.

The Mariners hold the top spot in the AL West by just 1.5 games over the Astros, which means winning this mid-week series against the Nationals is going to be important as Houston has a favorable series against the Athletics.

Let's dive into the odds and my best bets for tonight's series-opener.

Nationals vs. Mariners Odds, Run Line, and Total

Odds via DraftKings Sportsbook

Run Line

• Nationals +1.5 (-155)
• Mariners -1.5 (+130)

Moneyline

• Nationals +136
• Mariners -162

Total

• 8.5 (Over -105/Under -115)

Nationals vs. Mariners How to Watch

• Date: Tuesday, May 27
• Game Time: 9:40 PM EST
• Venue: T-Mobile Park
• How to Watch (TV): MASN 2, ROOTNW, MLBN (out-of-market only)
• Nationals Record: 24-29
• Mariners Record: 29-23

Nationals vs. Mariners Probable Pitchers

• Washington: Mitchell Parker, LHP (4-3 4.39 ERA)
• Seattle: Logan Evans, RHP (2-1, 3.33 ERA)

Nationals vs. Mariners Best Prop Bet

• Mitchell Parker OVER 4.5 Strikeouts (-105)

In today's edition of Painting Corners, I broke down why I'm backing Mitchell Parker to go over his strikeout total:

The Seattle Mariners have had a ton of issues when it comes to plate discipline lately. They have a strikeout rate of 23.3% in 2025 and a strikeout rate of 27.3% over the past 14 days, which is the second highest rate in the Majors in that time frame. They have also struck out on 25.6% of plate appearances against left-handed pitchers this season.

Tonight, they face Mitchell Parker of the Nationals, who has recorded 5+ strikeouts in two of his last three starts.

Nationals vs. Mariners Prediction and Pick

I'm going to take a shot on the Nationals as underdogs, but instead of betting on the full game, I'm going to take the First Five Inning Moneyline at +110. The Nationals have one of the worst bullpens in the Majors, sporting a bullpen ERA north of 6.00, so if we focus on just the first five innings, we can hopefully avoid an implosion by their relievers.

The Mariners' offense has been a middling unit of late, ranking 19th in OPS over the past 30 days at .701. That's below the Nationals, who come in at 15th in that time frame at .708.

We have also seen some recent struggles from the Mariners' starter, Logan Evans, who has allowed 3+ earned runs in two of his last three starts.

Let's take a chance on the Nationals getting off on the right foot tonight.

Pick: Nationals F5 ML +110 (via DraftKings)

---

Are you new to DraftKings? Sign up today and place a $5 bet to earn a guaranteed $200 in bonus bets. Win or lose, DraftKings will issue six $25 bonus bets instantly.

Odds refresh periodically and are subject to change.

If you or someone you know has a gambling problem and wants help, call 1-800-GAMBLER.

You can check out all of Iain's bets here!