As pointed out today by Matthew Carruth at The Hardball Times:
Derrek Lee has responded well after a down year in 2006 beset with injuries and issues. The batting average and on base percentage are back up to great levels and while the gap prowess has remained, the homerun power has curiously disappeared. Lee...has an unsustainable high BABIP of .410 despite a low groundball rate and a line drive rate under 20%. If the BABIP was around where you'd expect, Lee would be joining the list of struggling post-30 first basemen with Sexson and Delgado. If I'm a Cubs fan, I'm watching his power output very closely.