"He just sat backed and watched, which was good for us and obviously a bad deal for Miami" "He just checked out" said Stevenson when asked about Lebron. Stevenson even says himself that his defense had nothing to do with it.
Stevenson on Jim Rome, audio clip here -
http://tvider.com/view/56549


Edit:
Some people on the GB are claiming that Stephen A. Smith said LeBron is dealing with some "personal issues" right now.
I haven't seen any credible sources, but if you search "Stephen A. Smith" or "LeBron personal issues" on Twitter some tweets have been recently posted.
WuhlRadio Robert Wuhl Show
just heard @stephenasmith say LeBron's poor performance was due to personal issues similar to ones he's experienced in the recent past
@herculodge Jeff McMahon
Stephen A Smith Cannot Disclose LeBron James' Personal Issues That Interfered with Last Night's Game