Brett Gardner has been pretty good so far offensively for the Yankees this season. He is arguably one of only two Yankee regulars who is producing above the league average level of offensive production by wRC+. By that same metric, he is also likely having his strongest season at the major league level at the plate. Thanks to his usually effective base running skill set and a good showing in fielding metrics this year, Gardner is actually producing at a higher rate of WAR according to Fangraphs than Robinson Cano. So what is behind Gardner's increased output, and is it likely to continue?

Gardner's offensive progression through the Yankee system always seemed to take a logical path to maximize his greatest strengths. Blessed with lightning-quick speed and a good eye at the plate, Gardner honed his approach to work the count and turn walks into effective doubles by stealing bases with a greater than 82% rate of success. What he lacked in power he made up for with his eyes and legs. He is finally getting some attention this year for his production. After missing almost all of the 2012 season, Gardner has become a fixture at the top of a lineup that has few consistent sources of production. The interesting thing is that there are tangible signs that he has indeed changed his approach at the plate this year.

I excluded his major league seasons with fewer than 200 plate appearances. Some things jump out right away on this chart. He's walking less and striking out more, yet his on-base percentage is right in-line with most of his other years. Luck doesn't appear to be the reason since his BABIP is in-line with his 2010 season, and not radically higher than his career mark as well. What also stands out, though, is the bump up in power he's producing. He is cracking the .400 mark in slugging for the first time, and it's confirmed with a rise in his ISO reading. So on the surface it does look like Gardner is being more aggressive at the plate. It's causing his normally strong plate discipline to deteriorate producing less walks with more strikeouts, but he has gotten a concomitant bump up in his power production without losing any average from a lower BABIP. This is not the usual course for improvement in offensive production, so how is this working? Is he really being more aggressive, or is this just something that will regress away given time?

Gardner really is being more aggressive. His SWING% is up over 7% than in previous seasons, and that includes both pitches inside and outside of the strike zone. The league might have already noticed his new approach and adjusted by showing him fewer strikes inside the zone than before. It's not even half way through the season yet, but Gardner is seeing a (2%) reduction in Zone%. Here is the troubling part: It is one thing if a player is being a bit more aggressive and swinging at more pitches in the strike zone. That usually should equate to an increased contact rate on pitches in the zone if the strategy is working. However, in Gardner's case, his in the zone rate of contact has actually declined this year by a decent amount. He's effectively missing 5% more pitches inside the strike zone, and the same impact can be seen on the pitches he's swinging at outside of the zone. The reduced contact rate is a troubling sign with the more aggressive approach, and it suggests there might be an issue with his BABIP after all.

There is some good news, though, when looking at Gardner's batted-ball data. He might be swinging more often and missing more often, but the actual contact is of a better quality than he has historically produced. His LD% is up around 5%, and his FB% is up over 8%. Gardner is 29 years old, so it's not unexpected to see a bump up in a player's slugging production at this point in his career. In Gardner's case, this comes with a clear change in approach that is leading to more square contact. While Gardner's hitting improvement does seem to be explained by this data, it also appears to be confirming a puzzling trend in the deterioration of Gardner's speed. This year Gardner has had a poor success rate of only 65% on stolen base attempts. Unfortunately, his rate of infield hits suggests that recent figure might not be random. His IFH% has been trending down each year, and is now less than half of what it was. Player's blessed with extraordinary speed have tended to maintain that skill set longer through their careers than other abilities. So seeing Gardner struggling to steal bases coupled with the trend in declining in-field hits, suggests that perhaps his greatest skill set of all has materially declined unexpectedly. Part of the declining IFH% can be explained by the increase in fly balls, but the degree and the trend is well beyond what can be explained by the changes in his batted-ball data.

Gardner's change in approach does appear to be reaping legitimate rewards in the form of higher quality contact. Despite the reduction in walks and lower overall rates of contact, the increase in line drives and fly balls are offsetting the reduction in his normally stellar plate discipline. However, the deterioration in his greatest asset is perplexing at his age. One might wonder if his sudden change in approach is partly driven by a conscious recognition in a decline in his speed. While the path to his offensive improvements is unusual, it does not look unreasonable to believe that he could maintain his improvements in batted-ball performance. That's not to say, however, that the increased rates in swings and lower rates of contact are not a concern. If there is to be a problem with his new approach, then we'll likely see it manifested in a return to his historical LD% and FB%. Let's hope he keeps squaring the ball up well.

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