Entering the 2015 season, the Mets' infield defense had some questions surrounding it. Wilmer Flores was going to be at shortstop, mainly for his bat, and it was thought that he could be average, defensively, at the position. Mets fans knew what they were getting with Daniel Murphy at second base—he'd make most of the regular plays, wouldn't have much range, and would definitely Murph the occasional easy one.
Now as the Mets are four wins away from a championship, their defensive shortcomings could be a bad fit for a matchup with the Royals. With Ruben Tejada out, Flores is back as the everyday shortstop. If Murphy keeps hitting like he has, some defensive mistakes could be forgiven. Too many mistakes could cost the Mets games, because this Royals team gets timely hits and they don't strike out a ton.
The Royals struck out just 973 times this season, the fewest by far in the majors, well below the MLB average of 1,248. The Mets’ pitching staff struck out 1,337 batters this season. They have struck out 91 in nine playoff games, taking a lot of pressure off the fielders behind them. The Royals took just 383 bases on ball this season, the second fewest in the majors, only more than the Marlins’ 387.
That means the Royals are putting the ball in play a lot and testing the defenses they have faced. Their team batting average of .269 was second and they scored the seventh-most runs in baseball. They have upped that to a team batting average of .271 and have scored 63 runs in 11 playoff games.
Combine that with the fact that the Royals hit very well against hard-throwers—that is, pitchers who throw above 95+ MPH—and the Mets are going to be really tested in the field.