MLB Prop Bets: Seattle Mariners vs Kansas City Royals (May 3, 2026)
The Kansas City Royals (14-19) face the Seattle Mariners (16-18) at T-Mobile Park on Sunday at 4:10pm (ET). Let's take a look at the MLB Prop Bets for the matchup. Kris Bubic is the probable pitcher for the Royals, while Luis Castillo is the probable pitcher for the Mariners. The Mariners are favored to win at -126, while the Royals are at +104. The total runs line is set at 8.0, with OVER at -108 and UNDER at -112.
- The Royals (+161) have a 16-17 Run Line record this season, while the Mariners (-197) hold a record of 14-20.
- The Royals have a 14-17-2 O/U record this season (meaning 14 games have gone over the total runs line, 17 have gone under and two have resulted in a push). The Mariners have a 16-17-1 O/U record.
Scoring Insights
- The Royals are averaging 4.1 runs per game this season (25th in the league). Comparatively, the Mariners are averaging 4.2 (24th).
- In the field, the Royals are allowing 4.7 runs per game this season (19th in the league), while the Mariners are allowing an average of 4.0 runs (6th).
Let's take a look at how these teams perform in some other key statistical areas.
Batting Insights:
Batting Average
- Looking at their batting averages this season, the Royals are at .240 (ranking 16th in the Major leagues), while the Mariners are batting .232 (25th).
Home Runs
- In terms of total home runs this season, the Mariners have hit 38 (T12th in the Major Leagues). Meanwhile, the Royals have managed 33 (19th).
Runs Batted In
- Finally, looking at their runs batted in, the Royals have recorded 129 RBIs to rank 25th in the MLB this season. Comparatively, the Mariners have recorded 138 RBIs to rank T18th.
Pitching Insights:
Earned Run Average
- The Mariners have an earned run average of 3.68 this season (6th in the Majors), while The Royals have an ERA of 4.49 (20th).
Strikeouts
- Turning our attention to total strikeouts, the Royals have recorded 286 this season, ranking 12th in the MLB. Meanwhile, the Mariners rank T14th for total strikeouts, recording 282.
Opponent Batting Average
- Opponents are batting an average of .260 against the Mariners this season (24th in the Major Leagues). Comparatively, the Royals' opponents are at .245 (18th).
First Innings Moneyline
- Here are their first innings moneyline records in 2026.
| Total | Home | Road | Favorite | Underdog | Neutral | Last 10 | |
|---|---|---|---|---|---|---|---|
| Royals | 3-8-22 | 1-4-11 | 2-4-11 | 1-4-10 | 2-4-12 | 0-0-0 | 2-3-5 |
| Mariners | 9-9-16 | 8-7-4 | 1-2-12 | 9-8-13 | 0-1-3 | 0-0-0 | 1-3-6 |
Lead After Three Innings
The Royals are -110 to lead after three innings, while the Mariners are -120.
- Here are their records after the first three innings in 2026.
| Total | Home | Road | Favorite | Underdog | Neutral | Last 10 | |
|---|---|---|---|---|---|---|---|
| Royals | 10-15-8 | 6-6-4 | 4-9-4 | 4-8-3 | 6-7-5 | 0-0-0 | 2-5-3 |
| Mariners | 12-13-9 | 8-7-4 | 4-6-5 | 10-12-8 | 2-1-1 | 0-0-0 | 2-5-3 |
NRFI/YRFI
The NRFI market is paying -135 and the YRFI is paying +105.
- The NRFI is 21-12 in Royals games this season. The Mariners have a 13-21 NRFI record.
Last Time They Met
The Royals recorded a 3-2 extra innings victory over the Mariners at T-Mobile Park yesterday. Despite being on the wrong side of that result, Julio Rodriguez did what he could, hitting a home run. The Royals have now won three straight at T-Mobile Park against the Mariners.
