Because he's the current AL leader in wins above replacement, and there are some reasons to believe that he really might be. Don't forget the second basemen that started particularly strong last season- Rickie Weeks, Robinson Cano, Kelly Johnson- these guys all went on to 6+ WAR seasons, combining top-level offensive production with solid defense at a premium defensive position.
Weeks would seem to be the most obvious comparison for Kendrick among the bunch. Like Kendrick, Weeks was regarded as an elite hitting prospect in the minors. Like Kendrick, Weeks has thrived at times over the past five years but has struggled to put things together due to a series of injuries. And then last season, Weeks had a big April, managed to stay healthy all season, and put together one of the best performances of any player in the NL.
And given Kendrick's hot start, I'm wondering if this is the year that he matches those guys, particularly Weeks. It's not necessarily the fact that Kendrick's having a strong start- I'm sure that we've seen extended stretches of superb performance from the second baseman before. But what really intrigues me about Kendrick is how he's showing up at the top of so many leaderboards.
Kendrick has always been a high-contact hitter that depends on batting average to be productive offensively- his career BA is .296, and he's never had more than 10 homers or 28 walks in a single season. So offensively he's really only been able to go as far as his BABIP will take him, and over the past four years it hasn't been anywhere good: his BABIP has dropped every season of his career, .381 to .357 to .338 to .313 last season.
But this season, he's not simply depending on a high BABIP, and a strong batting average as a result of that, to be a successful hitter. Not at all. Sure, he has a .355 BABIP right now, but given his track record as a high-BABIP hitter and the small number of games played so far, that's an entirely reasonable mark to have. And frankly, that kind of BABIP alone certainly isn't enough to explain why he's the league-leader in WAR, not when other players have BABIP marks near or above the .500 level.
Right now, Kendrick's succeeding because he's doing things he's never done before. Like taking walks with frequency, and hitting home runs more often than once every 15 games. His career walk rate and isolated power marks of 4.0% and .136 are being destroyed right now; he's at 11.5% and .341 in the very same metrics. Last season, he hit 10 home runs and had 28 walks in 158 games, both of which set or matched career-high levels. Right now, he's on pace for 57 home runs and 86 walks in the same number of games as last season.
Obviously he's going to fall well short of those home run and walk numbers, but that's not necessarily the point here. Because if Kendrick is truly about to show more patience and power as he enters his age-27 season, we could finally be looking at his breakout performance, a la Cano or Weeks. At this point, it may not take much more than a bit of luck from the Health Fairy. And yes, I may in fact believe that the health of baseball players depends on the whims of a fairy.