In Major League Baseball’s postseason, the rules and guidelines that teams generally abide by regarding pitchers’ availability are tossed right out the window. Instead of every fifth day, elite starters often take the ball with only three days rest, sometimes two. Occasionally, they are called upon to make appearances out of the bullpen as well. Relievers are commonly asked to pitch longer and more frequently than they are accustomed to during the regular season. When a championship is on the line, managers naturally do whatever it takes to win by leaning on their best arms as much as possible.

It’s a whole new ballgame.

The Chicago Cubs qualified for their first World Series in 71 years without changing their normal pitching patterns–a benefit of having the best record in baseball and a staff made up of several top-tier starters. However, Chicago’s opponent in the National League Championship Series, the Los Angeles Dodgers, relied heavily on their ace, Clayton Kershaw.

In the divisional round, Kershaw won Game 1 against the Washington Nationals, then came back on short rest for Game 4. While his team got a victory that evening, Kershaw allowed 5 runs in just 6.2 innings. Dodgers manager Dave Roberts then elected to deploy Kershaw out of the bullpen with only one day off as L.A. clinched the series in Game 5.

Kershaw was spectacular in Game 2 of the NLDS just three nights later, hurling seven shutout innings in the Dodgers’ 1-0 win. But in Game 6, he gave up four earned runs in five innings, and his club was eliminated with a 5-0 defeat. Although Kershaw went five days between starts before his final outing, it’s quite possible his irregular schedule and excessive use throughout the playoffs took its toll.

The Cleveland Indians, on the other hand, arrived at the Fall Classic on the back of reliever Andrew Miller, who was named American League Championship Series MVP following multiple outstanding performances vs. the Toronto Blue Jays. In particular, Miller pitched on consecutive days in the first two games of the series, locking down 2-0 and 2-1 victories. Miller threw 1.2 innings in Game 1 and another two innings in Game 2, striking out 10 of the 12 batters he faced during his longest back-to-back appearances of the season.

In Game 1 of the World Series, Miller preserved Cleveland’s 6-0 triumph by throwing 46 pitches over two scoreless innings, his highest pitch count of the year. Miller has yet to surrender a run during the postseason, but eventually the extra workload may catch up to him. How far can Indians skipper Terry Francona push his hard-throwing lefty?

 

Questions regarding a pitcher’s ability to compete at an optimal level on short rest usually revolve around whether or not his arm will be at full strength. More often than not, this comes down to if he says he’s “good to go,” and what the manager feels in his gut.

Maybe the star hurler’s arm really is in decent shape after less than a usual amount of time off. Maybe it’s still sore, but he’s confident he can push through the pain. Or, maybe he’s fully aware that he’s far less than 100 percent, but there’s also no way he’ll let this chance to compete in the playoffs pass him by. Regardless, it’s a gamble, and it’s impossible for the manager to know the whole truth about the condition of his player.

What if arm strength isn’t the only thing that needs to be restored? Pitching in a major league game requires extraordinary physical and mental effort. Achieving a sufficient level of Recovery between appearances goes well beyond simply being capable of throwing the baseball.

Given the opportunity, wouldn’t a manager prefer to rely on some sort of empirical evidence, as opposed to just his instincts and what his player says?

WHOOP puts that option on the table.

There are physiological signs, “secrets your body is trying to tell you,” in the words of WHOOP founder Will Ahmed, that can be measured and used to indicate if an athlete is properly prepared to handle the demands of competition. Considering that individual players will respond differently to their workloads, there’s a need to be able to accurately quantify how each athlete is adapting to stress. But if every pitcher operates on the same schedule and routine throughout the year, how can the manager know who’s most likely to succeed on a more aggressive timetable in the playoffs?

WHOOP aims to mitigate the uncertainty associated with these critical decisions. Our 24/7 analysis provides an enormous amount of insight into what is “normal” for each athlete in terms of Recovery. Over time, the manager may learn that his No. 1 guy returns to baseline after just two or three days off, while another pitcher might take longer.

A season’s worth of WHOOP data could be an extraordinarily useful tool for Francona as he tries to determine just how much he can get out of Miller in the World Series.