|Arenado's sophomore season is off to a sizzling start (HoundSports)|
You see, Arenado was a pretty valuable baseball player last year, worth nearly four wins above replacement per Baseball-Reference. That's almost All-Star level. And yet he finished a distant seventh in the NL Rookie of the Year voting, tied with Evan Gattis, even though bWAR says he was more valuable than everyone that finished ahead of him except for Jose Fernandez (the winner) and Yasiel Puig (the runner-up). Arenado was also more valuable than every American League rookie who received votes (Wil Myers, Jose Iglesias, Chris Archer, etc.), none of whom exceeded 2.5 bWAR.
FanGraphs wasn't quite as generous, crediting Arenado with 2.7 fWAR, but that was still enough to make him the sixth most valuable rookie in baseball and fourth most valuable non-pitcher rookie, behind Puig, A.J. Pollock and Juan Lagares.
Point is, Nolan Arenado was good last year. What's interesting is how he was good. You'd expect a Rockies third baseman like him to post some pretty gaudy offensive numbers, similar to the ones Garrett Atkins or perhaps even Vinny Castilla used to put up.
He didn't. The 22 year-old did not hit for much power, with only 10 home runs, 52 RBI, a .405 slugging percentage and a ..138 ISo. He didn't hit for a high average or get on base very often. He was not a factor on the basepaths, stealing only two bases.
All of his value came from his defense, for which he won the Gold Glove, becoming the first rookie third baseman to win the Gold Glove since Frank Malzone in 1957, the award's first year (when only one was given out for both leagues). Arenado was a regular Brooks Robinson at the hot corner, saving 30 more runs with his glove than the average third baseman according to B-R (FanGraphs said 22.6). Among National League third basemen he was first in range factor, second in double plays, assists, and putouts, fourth in fielding percentage and fifth in total zone runs. His defense, by itself, was worth between two and three wins, more than enough to compensate for his mediocre offense.
And boy, was his offense mediocre. He hit .267/.301/.405, which doesn't look terrible for a rookie, especially in today's suppressed offensive climate. But for someone who plays half his games in Coors Field, those numbers weren't very good. The league-average non-pitcher would have been expected to hit .276/.344/.429 and post an OPS 67 points higher than Arenado's. Thus, even though his raw OPS of .706 was a touch better than the league average of .703, he wound up with an Adjusted OPS+ of 82, which is quite poor (18 percent below average). FanGraphs had him at 21 percent below average. He also struck more than three times for every walk and bounced into 16 double plays, a considerable number.
So Arenado had the defense thing down. Hitting, however was another story.
This year, it hasn't been. In addition to providing his elite defense, Arenado's providing great offense to go with it. Following an offseason dedicated to improving his hitting, he's enjoying a phenomenal start to his sophomore season. Last night he extended his league-best hitting streak to 25 with a two-run homer off fellow sophomore Martin Perez, two shy of Michael Cuddyer's franchise record and almost halfway to Joe DiMaggio's magical 56. He's batting .313/,336/.515, and his 42 hits rank second in the league to Paul Goldschmidt. With six home runs, nine doubles, 22 RBI and a .201 ISo. thus far, his power is much improved, too.
My first instinct was to check Arenado's BABiP, but at .316 it's nothing out of the ordinary. He's actually hitting fewer line drives and ground balls at the expense of more fly balls and pop-ups (which would suggest that he's swinging for the fences more, but his swinging strike rate and strikeout rates have gone down). His average should be in the pooper, but right now he's finding enough holes. That seems to be the only explanation, as there's nothing in his plate discipline/approach to account for this change. He's whiffing less often and making a little more contact, but all of his contact gains are coming on pitches outside the zone, which should be harder to square up and result in weaker contact.
Arenado's not going to keep hitting this well all season, but he's at an age (23) where improvement is expected, especially in the power department. He's probably getting a little lucky right now, but he's also probably just a better hitter. How much better is the true question, and right now it's too early to tell. I see him hitting .280/.320/.430 the rest of the way and finishing the season with close to 20 homers and 40 doubles. Those are good numbers anywhere, and I'm sure the second-place Rockies would happily take them going forward.
At the very least, Arenado has proven he's no longer a liability with the bat. Even he regresses to being just a league average hitter (or even a tick below), that still qualifies as a major improvement.