Before the robots take over - at least behind home plate - Major League Baseball ought to try something seemingly obvious: employ its best ball-strike callers as home plate umpires in the playoffs.

Remarkably, that's not something MLB is doing.

As many of those watching have noticed, umpires are having a tough time this postseason - whether it be down the first-base line or behind the plate. Those struggles were highlighted Tuesday night in Game 4 of the ALCS when home plate umpire Laz Diaz missed 21 ball and strike calls, including some crucial ones. Those calls gave the Houston Astros a nearly full-run advantage over the Boston Red Sox, according to UmpScorecards.com. The Red Sox believe a missed strike call contributed to many more runs allowed in the ninth inning. By any measure, it was a poor performance.

And it's not as if Diaz is one of MLB's best ball-strike callers and happened to have an off night. He ranked 64th out of 74 full-time umpires in strike-zone accuracy this season, according to Boston University finance professor Mark Williams' UmpScores database, which evaluates umpires based on pitch-tracking technology.

According to Williams' "bad-call rate" metric, 9.6% of Diaz's ball-strike decisions were incorrect this season. The major-league average among full-time umpires was 8.3%.