Jeff Hardy COULD have worked Mania
According to the May 16th, 2007 3rd Amendment to the WWE Wellness Policy , Jeff Hardy could have kept working TV, House Shows and even WrestleMania. The amendment reads as follows:
"Second Offense. In the event of a second positive result for drugs prohibited by this Policy other than marijuana, the Talent shall be fined an amount equal to 60 days' pay deducted from your downside guarantee on a weekly basis. The Company may, at its discretion, schedule the Talent to work selected televised events without pay, pay-per-views with pay and non-televised live events with a $200 stipend per event during the 60-day suspension period. Alternatively, in cases where the Talent appears to be in need of a drug rehabilitation program, the Talent shall not be assigned to work until the individual has successfully completed the drug rehabilitation program. However, regardless of the length of the program, the Talent's fine shall be limited to 60 days' pay."
The first portion indicates that technically under their own policy, that WWE could have had him work WrestleMania as well as the TV and House Shows shows leading into the big event. The catch looks to be the second half of the amendment, which states, "Alternatively, in cases where the Talent appears to be in need of a drug rehabilitation program, the Talent shall not be assigned to work until the individual has successfully completed the drug rehabilitation program."
When Jeff Hardy first left WWE (and ended up going to TNA for a time) it was due to drug issues. At the time the company asked that he enter a drug rehabilitation program, and Hardy refused.