How much is too much when it comes to playoff pitcher usage?

October baseball is a much different game than the one played during the regular season.

For all the bullpen games teams use during the season to get through injuries or to hide temporary roster imbalances, the MLB playoffs increasingly have become the domain of relief pitchers.

Relievers combined to throw 41.2% of innings in the regular season this year, and their share of work was up to 48.9% through division-round play. It ranged between 44.2% and 53.4% during the previous four postseasons.

Relievers have proven to be more effective than starters in four of the last five postseasons:

October baseball also features more familiarity between opponents as series grow to best-of-five and best-of-seven, starting with the division series. Hitters never see the same starting pitcher twice in a three-game regular-season series, and rarely face a reliever more than twice.

Playoff series are not only longer, they also have added off days to accommodate travel and TV scheduling. The extra rest means teams can allocate a greater share of their innings to their two best starters and their high-leverage relievers, particularly in the division series.

While these dynamics seem great for teams with top-end pitchers, there can be a cost to exposing their best arms to the same hitters repeatedly during a series.

Batters generally gain an edge over both starters and relievers the more often they face them in a series.

Many baseball fans are aware of the concept of the third time through the order penalty for starting pitchers. Splits show their performance generally declines the third time they face an opponent in a game - in part because batters become more familiar with their stuff and release points, etc.

That holds up in the postseason, too, and if often guides pitching strategy.

Since the 2020 postseason, batters own a .310 wOBA against starters the first time facing them in a series, a .315 mark in their second plate appearance, .323 in their third, and .322 in their fourth.

The sample size drops off after three plate appearances and the results become more noisy. Hitters post a curious dip the fifth time they see a starter (.272) before improving to .400 in their sixth plate appearance and .340 in their seventh.

For instance, the Tigers seemingly had a significant edge with Tarik Skubal on the mound twice in the ALDS versus the Guardians. But Cleveland eventually got to the AL Cy Young favorite in Game 5, his second start.

Lane Thomas blasted a grand slam against Skubal in the fifth inning of the decider, and it occurred during Thomas' sixth plate appearance of the series against Skubal, an unusual amount of volume within a five-day period.

Cleveland leadoff man Steven Kwan went 2-for-3 against Skubal in Game 5 and was on base for the grand slam.

"When he hits the spot, you can't really do anything about it, but just being able to see that over and over is super helpful," Kwan told me following Game 5. "Being able to have that dialogue with other guys, too, and kind of formulate a team plan, I think all of those go into it."

Thomas was sitting on a fastball for the first pitch of his fifth-inning blast because he picked something up after facing Skubal in the third inning, also with the bases loaded.

"My first time with the bases loaded, I kind of was looking soft," Thomas said. "I thought in that situation he wasn't going to come at me, and he proved me wrong, and then the next time I was like, you know, I gotta be ready for the fastball. And he threw a good one that I could hit. "

Perhaps even more interesting is what happens with relievers the more they face an opponent in a long series. The story's similar and the trend even more pronounced:

Opponents post a .298 wOBA against relievers in their first plate appearance facing them, .300 in their second, and jump to .321 in their third. (The results become noisier as the sample size shrinks.)

Relievers improve to a .282 wOBA when facing opponents a fourth time in a series, but batters then gain a massive edge, posting a .450 wOBA the fifth time facing a reliever in a series.

Managers may want to consider limiting how many times specific batters see relievers in a series.

For instance, Luke Weaver and Clay Holmes have appeared in every Yankees postseason game. Weaver recorded a five-out save Monday in Game 1 of the ALCS and pitched again Tuesday, in a non-save situation in the ninth, allowing a home run to José Ramirez.

Guardians relievers Cade Smith and Tim Herrin became the 12th and 13th pitchers to appear in all five games of a division-round series in the ALDS against the Tigers - and this is a time when a three-batter minimum rule exists. They were effective but perhaps pushing the limits.

No pitcher's appeared in all seven games of a league championship series, although 10 pitchers have appeared in six games, including the Astros' Bryan Abreu last year, the first to do it in the three-batter-minimum era.

Two pitchers have thrown in all seven games of a World Series: Brandon Morrow in 2017 for the Dodgers, and Darold Knowles in the 1973 World Series for the Athletics.

In 2017, that usage - and Houston's sign-stealing - might have caught up to Morrow. He blew up in Game 5, allowing four earned runs without recording an out, giving up home runs to George Springer and Carlos Correa and a double to Jose Altuve. It was the third time he faced Altuve, Correa, and Springer in the series. He allowed one run in his first three innings of the series.

Guardians manager Stephen Vogt stayed away from his best relievers in Monday's Game 1's loss to the Yankees after employing a heavy bullpen strategy against the Tigers last week. Vogt seemed to almost punt the game to rest his top arms, after his bullpen absorbed 64% of ALDS innings pitched.

In Game 5 of the ALDS, Vogt brought in Smith in the third inning. But against the Yankees in Game 1, he summoned rookie Joey Cantillo with the bases loaded in the third. Cantillo was one of the last players selected for the roster and he seemed overwhelmed in the moment, spiking multiple wild pitches into the dirt, allowing two runs to score.

"We asked a lot of our bullpen the last week," Vogt said before Game 1. "So going into (Monday), we know that they've got a lot of bullets that they've used. These guys work hard. They're strong. We're going to approach each game like we have all year. That is, 'Let's win today, and (then) we'll worry about tomorrow.' At the same time, we're very mindful of the workload that our guys have had. So maybe we can't overextend anybody, nor do we want to."

The LCS schedule means Vogt has to manage his pitchers differently. Against Detroit, Cleveland enjoyed off days after Game 1, Game 2, and Game 4, and had a week off before the ALDS even began. There are only two scheduled off days for ALCS travel (Oct. 16 and 20).

It'll be difficult to be as aggressive with bullpen usage. Perhaps holding back their best relievers Monday means they'll benefit later in the series.

After all, in October baseball, it turns out there can be too much of a good thing when it comes to using a great arm.

Travis Sawchik is theScore's senior baseball writer.