Article: How Do The Toronto Blue Jays Stack Up Against The Seattle Mariners In The ALCS?

[Bob Ritchie]

Before the American League Division Series between the Toronto Blue Jays and the New York Yankees began, I examined how the Blue Jays compared with recent World Series teams. The analysis consisted of two parts. The first part of the analysis was titled, How Does the Blue Jays’ Offence Stack Up to That of Recent World Series Teams?. The second part was titled, How Does the Blue Jays’ Pitching and Defence Stack Up to That of Recent World Series Teams? Fast forward to today, Game One of the American League Championship Series. Hence, it is time to examine how the Toronto Blue Jays measure up against the Seattle Mariners.

I organized the analysis of Toronto’s and Seattle’s batting and baserunning as follows:

• Key batting metrics (wRC+, runs, home runs, and others)
• Distribution of runs scored between home runs and balls in play
• Hitting performance by pitcher handedness, including runners in scoring position
• Batting order balance and hitting by inning segments
• Baserunning

The analysis of Toronto’s and Seattle’s pitching and defence is structured as follows:

• Distribution of runs allowed
• Starting pitchers
• Relievers
• Defence

As I noted in the previous articles, compared to the regular season, the following observations concerning the postseason are essential to keep in mind:

• Runs per game are lower.
• Home runs per game are similar.
• Runs per home run are alike.
• The share of runs via home runs is higher.

Batting and Base Running
Table 1 shows the key batting metrics of the Blue Jays and Mariners. Toronto ranks much better in runs, K%, and OBP, whereas Seattle has generated more power (home runs and ISO) than Toronto. In many areas (home runs, ISO, and K%), Seattle resembles the Yankees, which ranked first in home runs and ISO, and 25th in K%. However, concerning each team’s leading home-run hitter, Seattle had a higher percentage of home runs attributable to Cal Raleigh (25%) than New York had with Aaron Judge (19%) or Toronto with George Springer (17%). Therefore, given Seattle’s higher reliance on Raleigh’s home run production than Toronto’s dependence on Springer’s, if Toronto’s pitchers could curtail Raleigh’s home run output, it would reduce Seattle’s home run hitting advantage over Toronto. However, in his career, Raleigh has hit a home run against Toronto every 8.4 at-bats, a better rate than his overall 14.1 AB/Home Run rate. It will be a challenge, but possible, for Toronto to limit Raleigh’s home run output.

Table 2 shows the distribution of runs scored. That is, what percentage of runs scored is the result of home runs, and what percentage is attributable to balls in play, balks, and other non-home run plays. For simplicity’s sake, I will lump all runs not arising from home runs to be runs from balls in play (“BIP”).

Based on the conclusions from my previous article, compared to the 2025 regular season, the number of runs scored per game will likely be lower in the ALCS, and the runs per home run and home run rate will remain materially the same. Therefore, teams that have a higher share of runs scored via home runs will likely score more runs in total compared to teams with a lower share of runs scored attributable to home runs. Why? Because runs from BIP per game are likely to decline, which makes sense because postseason teams typically have good pitching staffs. Consequently, to score runs from BIP, teams need to string non-homer hits together, which is more difficult when facing good pitching.

Accordingly, given Seattle’s elevated percentage of runs scored attributable to home runs (50% versus Toronto’s 39%), the Blue Jays may find it more difficult than Seattle to score runs, all things being equal. However, all things are not equal. Toronto’s run total was four percent higher than Seattle’s. In other words, Toronto’s offence was more potent than Seattle’s in the run-scoring department.

Table 3 shows the wRC+ marks of the Blue Jays and Mariners by pitcher handedness. The upper part of the table reveals that, in all situations, Toronto and Seattle do not have significant splits. However, the table’s lower portion shows two facts. First, Toronto has performed well in RISP situations and has insignificant handedness splits. Second, Seattle has not hit as well as Toronto in RISP situations, and the Mariners have been below average when facing left-handers with runners in scoring position. Accordingly, Seattle’s 91 wRC+ in RISP situations may provide Toronto with opportunities to use its left-handed relievers in critical situations successfully. However, it is worth noting that RISP numbers tend to be volatile due to small sample sizes.

For batting order and wRC+ performance by innings, please take a look at Table 4. The numbers show a slight difference between the Blue Jays and the Mariners, whether by batting order or by innings (before the seventh or after the sixth). 

The last item on the offensive front is baserunning. Table 5 shows that Toronto and Seattle are below average. Toronto is better at taking extra bases, but Seattle is more proficient at stealing bases.

Pitching and Defence
Table 6 displays the distribution of runs allowed by the two teams. There is a slight difference in the percentage of runs allowed via home runs between Toronto (46%) and Seattle (43%). However, because the Mariners score runs from home runs at a higher rate than the Blue Jays (50% versus 39%), Toronto projects to allow more runs than Seattle, all things being equal, which, as noted, they are not.

Regarding starting pitchers, I anticipate that each team will use four starters in the ALCS. Accordingly, I presented the unweighted average of the 2025 regular season numbers of two starter groups for both teams. Behold Table 7!

For Toronto, the first three starter locks are Kevin Gausman, Shane Bieber, and Trey Yesavage. I expect either Chris Bassitt or Max Scherzer to be the fourth starter. Regarding Seattle, I expect Luis Castillo, Logan Gilbert, and George Kirby to be part of their rotation. The Mariners are likely to add either Bryce Miller or Bryan Woo to the noted trio.

As Table 7 shows, a group’s numbers are dependent on who the fourth starter will be. For example, if Toronto adds Scherzer instead of Bassitt, Toronto’s ERA jumps from 88 to 96. In Seattle’s case, the average ERA- would be 110 with Miller and 92 with Woo. Notably, Woo recently suffered a pectoral injury and has not appeared in an MLB game since September 19. However, before his injury, Woo posted a 76 ERA- and an 86 FIP-. He may return for the ALCS. Miller posted a 148 ERA- and a 130 FIP- during the regular season. Notably, Miller generated a 108 ERA- and a 54 FIP- in four and a third innings against the Tigers.

Overall, I would give Seattle’s projected starting rotation a slight advantage over Toronto’s. First, Bieber and Yesavage did not pitch many innings during the regular season. Bieber had 40 innings, and Yesavage had 14. However, to the extent Seattle has an advantage regarding starters, Kirby, Gilbert, and Castillo pitched in Friday’s game against the Tigers. Kirby threw 64 pitches, and Gilbert and Castillo had 34 and 15, respectively. Perhaps Gilbert and Castillo, who appeared as relivers on Friday, will encounter abnormal fatigue due to Friday’s appearances.

Regarding bullpens, Table 8 provides the necessary information. The Toronto and Seattle bullpens have performed similarly. However, one clear advantage for Seattle is their closer, Andrés Muñoz, who posted ERA-, FIP-, and K-BB% marks of 45, 60, and 21.7, respectively, in 62 innings. Toronto’s closer, Jeff Hoffman, recorded ERA-, FIP-, and K-BB% scores of 107, 116, and 19.9, respectively, in 68 innings. On the bright side, Toronto’s bullpen has not pitched since October 8, whereas Seattle’s reliever corps last pitched on October 10. Furthermore, Toronto’s relievers have pitched seven fewer innings than Seattle’s (20 versus 27). Hence, the Blue Jays’ bullpen may be a little more rested than the Mariners.

A final thought regarding pitchers: if the trend depicted in the chart below continues, each team’s bullpen will pitch as many, if not more, innings than their respective starting rotations. Accordingly, Toronto may mitigate its apparent disadvantage in starting rotations due to more reliever usage in the ALCS than in the regular season.

One area where Toronto is clearly better than Seattle is team defence. As Table 9 shows, Toronto’s defence is superior in the noted areas: infield, outfield, and catching.

Summary time!

Summary - Batting and Base Running 
The key points from the analysis are as follows:

• Concerning run scoring, not striking out, and getting on base, the Blue Jays are better than the Mariners.
• Seattle generates more power but is more dependent on home runs from its home run leader (Raleigh) than Toronto (Springer).
• Because Toronto is more reliant on scoring runs from balls in play, the Blue Jays may be challenged to score runs than Seattle because the Mariners have generated 50% of their runs via home runs.
• Neither team has pronounced wRC+ splits by pitcher handedness. However, Seattle has struggled against left-handers with runners in scoring position.
• Neither team runs the bases well.

Summary – Pitching and Defence
The critical points from the analysis are as follows:

• Although there is minimal difference between the percentage of runs allowed via home runs by Toronto and Seattle, there is, in theory, upward pressure on Toronto’s runs allowed metric because the Seattle offence scores more runs via home runs at a higher rate than Toronto.
• Seattle’s projected starters have a slight edge over Toronto’s. However, if Woo is not on the ALCS roster or falters because of inactivity, Toronto projects to have a smidgen of an edge.
• The bullpens of the two ballclubs are both good. However, Seattle’s closer (Muñoz) is elite, and Toronto’s (Hoffman) is not.
• The Blue Jays’ defence is elite, and Seattle’s is worse than the Yankees.’

The Last Word
Given the circumstances, I give the edge to Toronto primarily because of better overall hitting, run scoring, and superior defence.

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