Aaron Hill's struggles in 2010 are somewhat deceiving. He's very much the same player he was in 2007, when he first broke out by hitting .291/.333/.459 over 657 plate appearances, and, aside from his fluke homer total, the same player he was last season when he finished with a line of .286/.330/.499. The one major difference is that of his batting average on balls in play, but this deserves a deeper look than a simple wave of the hand with the "regression fixes all" mantra following.
Hill, in spite of his sub-Mendoza line batting average, has an Isolated Power of .164—that's four points below his 2007 level, and 13 points ahead of his career average. There are two ways to look at this—2009 was a career year for Hill, and while he's going to put up some good-looking seasons, he may not approach the same level of sexy he reached last year. In that view, seasons like 2007 are the norm for Hill, and while they are valuable, he's no Chase Utley–that's why he was ranked as a four-star player and not a five-star one, like the Phil's second baseman. The other way of looking at this is that Hill has managed to maintain a serious amount of his pop in spite of his struggles, and that he would be much closer to his 2009 production were his problems to be scrubbed from the record.
Before we can say that the latter is the case, we need to identify what Hill's problem is. We've established his BABIP is low at .184—it's at least 100 points low, relative to the average—but the why is the important thing to find out in order to see if this is fixable or if it's something to be concerned about into the future.
His strikeout rate checks out—15.2 percent is in the same neighborhood as last season as well as other years of his career (no, strikeouts are not factored into BABIP directly, since it's a batting average on balls in play, but fewer chances for balls in play due to exceptionally high whiff rates could cause some small sample oddities). While line drives do not correlate directly with BABIP, the fact that he's all the way down at nine percent for his liner rate is a warning sign. Hill is generally 10 percentage points higher than that, closer to the league average. He hasn't replaced the liners with groundballs—instead, they have turned into flyballs. That would be excellent if he had last season's nearly 15 percent HR/FB rate, but he's down at nine percent—the second-best rate of his career, but the sheer number of flyballs he is hitting are killing his batting average and BABIP.
His G/F ratio is 0.7, and 54 percent of his balls in play are flyballs. That's great when they fly over the fence—21 percent of all of his hits have been homers—but not so great when you can't hit a double to save your life (Hill hit 47 doubles in 2007 and 37 in 2009, but has just 11 this year) and singles are amongst the missing because outfielders can camp under half of what you put in play. Hill may have something amiss in his swing that is keeping his swing from being as level as it needs to be, and is keeping him from hitting the ball squarely, but we can identify part of the problem in his approach.
Hill is swinging at 33 percent of pitches outside of the strike zone, a career high for the Blue Jay second baseman. He's also making far more contact with pitches outside of the zone than he has in the past—72.1 percent, when his career average is 60 percent. More contact can be a good thing, unless you aren't hitting the ball squarely. Based on the results of Hill's season so far, as well as the absurd drop in his liners and the increase in his flyballs, one would have to think that either the official scorers have lost all ability to score the game, or Hill has lost all ability to square up on a ball and drive it where the fielders can't get to it. Given his .184 BABIP, and the fact that this official scorer uprising hasn't destroyed the fantasy seasons of any other Jays, we're going to go with the second option.
Whether or not Hill's issue is temporary or not is the main concern. This is different from his 2008 problem, when his power was sapped but he continued to pick up hits. Hill has shown himself to be a very good-to-great hitter in the past, and you should show some faith in him because of it, especially because you have to sell low on him in a trade to get rid of him, but mostly because this is the kind of anomaly that can disappear as fast as it appeared once the player gets a handle on the situation. It's painful if you own him, but this is not the kind of thing that makes Hill a lost cause.