Unfortunately, Sam is on his way back to crazy town, and with that Lucifer will be making a reappearance. Jared told Examiner.com some spoilers regarding how Sam will again be losing touch with reality:
"And quite frankly where we are in the season [shooting] now is he loses everything. He loses his way to figure out reality and falsehood…It ends up driving him crazy. Crazy crazy where he can’t function anymore."
Mark Pellegrino is filming his Lucifer scenes as we speak, and Jared said his return will again occur in Sam's mind:
"Mark Pellegrino comes back as a vision in Sam’s head. Sam finds himself in a situation where he has to decide between engaging this vision and risking the consequences or ignoring and risking other consequences involving his brother. So we’ll see what happens."