Gardner has all the tools to be a solid leadoff hitter. What he lacks is consistency when using them. He is undoubtedly one of the fastest players in baseball, yet always appears to be hesitant to take off from first, which resulted in only 20 stolen bases in 2015. Gardner hasn't stolen more than 25 bases since posting 47 and 49 in 2010 and 2011; numbers he needs to produce again to truly be a fantasy asset.
Gardner does hit better in the leadoff spot, which is a problem considering the Yankees already have a leadoff hitter in Jacoby Ellsbury. Last season, Gardner batted .281 when leading off and .246 batting in the two hole. His production was slightly higher batting second, but his job is to get on base, run, and don't stop running.
The best thing that could potentially happen for Gardner's fantasy value is if he is traded. The Orioles, White Sox, Cubs, Indians, Angels, and Cardinals have all shown interest, most of which lack a true center fielder and leadoff hitter. His run total was high last season at 94 but so were his strikeouts, 135. Gardner is ranked in the top 30 of outfielders, but it would be wise to wait and see if he lands elsewhere. He's a third outfielder, that should be drafted later in any draft.