Kiel was charged with one count of possession for sale and two counts of transportation of the controlled substance pharmaceutical codeine, sources told ESPN.
The law enforcement sources said several plain clothes DEA agents appeared at the Chargers' facility Tuesday morning with an arrest warrant, searched his locker and car, and took Kiel away.
The Chargers, who are coming off a bye week, were on the practice field at the time.
In a statement, team spokesman Bill Johnston said: "We're aware
of an off-the-field situation involving Terrence Kiel and we're
monitoring the situation. Due to the personal nature of the ongoing
legal investigation, the Chargers are withholding further comment
until the matter is resolved legally."
Kiel was booked and released after posting $150,000 bond.
Chargers officials were not returning phone calls Tuesday night. Kiel and his agent also could not be reached for comment.
Kiel, a fourth-year veteran from Texas A&M, is the starting strong safety for the 2-0 Chargers, who play the 3-0 Ravens on Sunday. Kiel's status for the game is unclear.
Drafted in the second round in 2003, Kiel was expected to start that season for the Chargers before he was shot three times in an attempted carjacking in Houston in July of that year.
Kiel is making $500,000 this year and has two years left on his contract.
This is the second major off-field incident of the season for the Chargers. Linebacker Steve Foley was shot three times Sep. 3 when he confronted an off-duty police officer who had followed his vehicle on suspicion of drunken driving.