San Francisco Giants pitcher Madison Bumgarner made headlines last week on Opening Day of the Major League Baseball season when he hit two home runs in his team’s 6-5 loss to the Arizona Diamondbacks. You don’t often see pitchers hit so well, especially pitchers that also throw as effectively as Bumgarner.

However, MadBum’s career slash line as a hitter reveals an interesting trend that also coincides with his improbable 2014 postseason pitching performance. Prior to the 2014 MLB season, Bumgarner was just as bad of a hitter as any average MLB pitcher.

In his first 224 at-bats as an MLB hitter, MadBum hit .138/.186/.192, displaying minimal power with just eight extra-base hits (including two HRs, both coming in 2012). However, from 2014-2016, the Giants lefty suddenly became a threat at the plate, putting up a  .227/.275/.428 line over 229 ABs. This shocking and sudden improvement included 12 HRs among 22 XBHs in total.

How does any MLB hitter, let alone a pitcher, see that kind of improvement in a slash line? Good question. The jump in his hitting numbers came during the same season where MadBum put a mediocre Giants team on his shoulders in the postseason, carrying them to an unlikely World Series championship despite surpassing his career-high figure for innings pitched by a significant percentage without any sign of fatigue whatsoever.

During that 2014 regular season, Bumgarner tossed a (then) career-high 217 1/3 innings (with a 2.98 ERA) and then proceeded to throw another 52 2/3 innings in October at even higher level (1.03 ERA). In era when MLB teams often protect their young arms from overuse, the Giants benefitted from Bumgarner’s seemingly endless reservoir of arm strength. At a time when his cannon should have been falling off, the left arm of MadBum simply got stronger.

Prior to the 2014 postseason, Bumgarner had posted a 3.68 ERA in 36 2/3 postseason innings. Thus, his extreme and sudden hitting improvement coincided with his extreme and sudden postseason invincibility.

Draw your own conclusions, but consider this slash line comparison below from another Giants player in the past, with a significant demarcation line between two eras.

BEFORE: .290/.398/.556
AFTER: .319/.505/.721

Improvements like that are rare, inexplicable and illogical. Maybe someday the mystery of MadBum’s sudden slash line improvement will be solved. Then again, maybe they won’t.