WWE World Heavyweight champion Brock Lesnar was backstage at Raw but was not used. Lesnar flew on his private plane to Nashville for the taping earlier in the day on Monday.
According to those who saw him backstage yesterday, Lesnar was obviously angry about something and one source claimed he walked out of the taping before it ended.

There are different stories making the rounds, but PWInsider.com has been told it was not something on the creative end that set Lesnar off, but something regarding his business relationship with WWE. No one we spoke with was willing to elaborate beyond that, but several made it clear it had nothing to do with any planned booking.

Vince McMahon acknowledged the issue during a Smackdown production meeting today, a source claimed, but did not elaborate on the issue. Lesnar has returned home to Minnesota and is not backstage at Smackdown.

Lesnar is not advertised to appear again for WWE until the 3/9 Raw taping in Pittsburgh, PA, which gives WWE several weeks to work out whatever the issue is.