Rob Van Dam's contract structure of working 90 days then getting time off was something he and Triple H came up with. Vince McMahon approved the idea when it was pitched to him. RVD has other projects he wants to work on, which is why he didn't want to work for extended periods. He is allowed to work with other wrestling companies during his time off but can't appear on their TV or DVD releases. The original contract was for 90 days and then they'd re-evaluate things. As of Monday, he had not signed a new short-term WWE contract.
WWE creative wants to have Van Dam back for the Royal Rumble and book him through Extreme Rules. This would be longer than 90 days. Once again, they would need to come to terms on another short-term contract and as of now, that has not happened and nothing has been agreed upon. It remains to be seen if he'll re-sign with the company with some saying Van Dam was not all that thrilled with his latest WWE run. According to a backstage source, someone recently said something to RVD about WWE being "better than TNA" and Van Dam gave an odd reaction, basically giving the impression that it was "sort of the same".
We'll keep you posted as we hear more.