Daunte Culpepper was on the Dolphins' practice field for the start of a weekend minicamp Friday, one day after asking for his release and two days after Miami completed a trade with Kansas City for Trent Green -- who's taking over at quarterback. Culpepper left the field and headed into the Dolphins training facility about halfway through the scheduled practice. He walked off the field with a member of the Dolphins security staff. The team did not give an immediate explanation.