What Explains Blue Jays Improvement?

Starting 13 July, the Blue Jays had a new interim manager, John Schneider. A miraculous improvement happened immediately:

• 2 wins, 9 losses in 11 games immediately prior to new interim manager (2-12 July).
• 9 wins, 2 losses in 11 games immediately after new interim manager (13-28 July).

Some might say change was because of small sample size or because they ended a normal slump. They would be hand-waving at a huge dramatic change (2 wins to 9 wins), perhaps losing an opportunity to discover an insight.

“I like to be aggressive. I like having fun. I always think that when guys are comfortable, that’s the best version of the player you’re going to get.” — John Schneider, interim manager of Blue Jays

Some might say improvement happened because of a new interim manager. Perhaps he made more aggressive decisions as manager. Perhaps he made the players more comfortable. Although I very much appreciate the value of a great manager, I’m incredulous that John Schneider was responsible for the Blue Jays’ miraculous improvement.

Let’s look at other explanations.

Home-Away Split

This season, the Blue Jays record at home (.615 winning percent) was better than their record away (.489 winning percent). However, the expected win difference was only a half win, far less than the actual 7-win difference. Calculation results follows:

• Expected 5.9 wins, 5.1 losses in 11 games immediately prior to new interim manager (4 home, 7 away).
• Expected 6.4 wins, 4.6 losses in 11 games immediately after new interim manager (8 home, 3 away).

Relief Pitching

This season, some statistics show only small differences between Blue Jays starting pitching and relief pitching (ERA 3.98 vs 3.93, OPS allowed .735 vs .702).

Looking at runs allowed per game immediately prior and immediately after the new manager showed that relief pitching was better after, but not by enough to explain a 7-win difference.

• 1.3 reliever runs allowed per game in 9 games prior to new interim manager (excluded two bullpen games).
• 1.0 reliever runs allowed per game in 11 games immediately after new interim manager.

Starting Pitching

Looking at results immediately prior and immediately after the new manager showed that starting pitching was better after, by enough to explain roughly half the 7-win difference.

• Starters allowed 3-or-less earned runs in 6 of 9 games immediately prior to new interim manager (excluded two bullpen games).
• Starters allowed 3-or-less earned runs in 10 of 11 games immediately after new interim manager.

Batting

First thing to note is that the same batters appeared before and after the new interim manager (except for Gabriel Moreno with 18 PAs and Zack Collins with 2 PAs). A significant change cannot be explained by different batters.

Let’s look at batting in three ways:

• What was the Weighted On-Base Batting Average (wOBA)?
• How many games did the Blue Jays score at least 4 runs?
• How many innings did the Blue Jays score 2 or more runs?

Weighted On-Base Batting Average (wOBA).

Looking at PA weighted wOBA for the Blue Jays immediately prior and immediately after the new manager showed a dramatic improvement from league average to well above average.

• .306 wOBA in 11 games immediately prior to new interim manager (2-12 July).
• .388 wOBA in 11 games immediately after new interim manager (13-28 July).

For comparison, from 2-28 July the league average was .313 wOBA

The following table shows 8 of 12 batters improved their wOBA.

Blue Jays Batters, 2 July to 28 July, 2022, minimum 15 PAs. Data from Baseball Savant.

Games with Blue Jays scoring at least 4 runs. The Blue Jays had a dramatic increase in the number of games that they scored at least 4 runs.

• 3 games with at least 4 runs scored in 11 games immediately prior to new interim manager.
• 9 games with at least 4 runs scored in 11 games immediately after new interim manager.

Big innings per game. The Blue Jays had a dramatic difference in 2-run innings and 3-or-more run innings.

• 5 2-run innings and zero 3-or-more-run innings in 11 games immediately prior to new interim manager.
• 9 2-run innings and 12 3-or-more-runs innings in 11 games immediately after new interim manager.

A possible conclusion is that perhaps the Blue Jays players decided to give their full effort after scoring 2 runs in an inning. That attitude of aggressively pressing to increase their advantage and perhaps dishearten their opponent may have been missing prior to the new manager.

“I really can’t emphasize enough how much pressure we can put on a pitcher when we get guys on base. Working walks is something we’ve been preaching all year, and doing damage after that has been big.” — John Schneider, new interim manager of Blue Jays

If innings with multiple runs scores are any indication, the Diamondbacks have something in common with the Blue Jays. In games played in the same range of dates (2 to 28 July), the Diamondbacks had more 2-run innings (17 vs 14) and more 3-or-more-runs innings (13 vs 12). Similar to John Schneider, Torey Lovullo has talked about swinging at pitches when the batter knows he can do damage.

My conclusion based on looking at batting in three ways was that better batting explained roughly half the 7-win difference immediately after the new interim manager.

Summary.

The dramatic improvement of the Blue Jays win-loss record immediately after the new interim manager was likely caused by better starting pitching and better batting, especially more big innings. Minor contributors were they played more home games and their relief pitching was slightly better.