He is free on $2,000 bond.
The Phillies confirmed the arrest, but said, "Because this is an open case, we will not comment further at this time."
Pinellas County Sheriff's Office public information officer Cecilia Barreda said the incident originally occurred June 11.
A patrol deputy spotted Gillies standing on the shoulder of Rt. 19., near Enterprise Blvd., in Clearwater. Gillies was waving a white shirt in the air at passing motorists.
The deputy approached Gillies and noticed he appeared intoxicated. Gillies told the deputy he was waving his shirt because he was looking for his friends -- and he thought it would help them see him. He also said he was walking back to his hotel, which was the La Quinta Inn.
Gillies said he had spent several hours that evening at The Freaki Tiki Bar, which is not far from where the deputy spotted him.
The deputy asked Gillies if he had enough money to take a cab to his hotel, which is located less than a mile from the Phillies' Spring Training facility and where most Phillies Minor League players stay during Spring Training and during the season. Gillies did not have enough money, so the deputy offered him a ride.
Just after Gillies exited the cruiser at the hotel, the deputy spotted a small bag of a white powdery substance on the floorboard of the back seat, where Gillies had been sitting. The deputy confronted Gillies about the substance.
The deputy took the substance into evidence to be analyzed and identified. Gillies was told he could be charged at a later date, pending those results.
The results returned positive for cocaine Thursday. Deputies made contact with Gillies at 12:30 a.m. Friday at his hotel and arrested him for possession of a controlled substance. Gillies was brought to the Pinellas County jail. He was booked at 1:48 a.m., and released on bond at 10:52 a.m.
An arraignment could come in three to four weeks, although Gillies' lawyer could enter a written plea of not guilty. In that case, a trial date would be set.
The Phillies acquired Gillies from the Seattle Mariners in December in the Lee trade. He opened the season with Double-A Reading, but had not played in months because of an injured left hamstring. He had played with the rookie-level Gulf Coast League Phillies in Clearwater recently on a rehab assignment.
Gillies hit .238 with two homers, six RBIs, a .286 on-base percentage and a .333 slugging percentage in 26 games with Reading. He played in two games with the GCL Phillies.
Gillies joined the Phillies along with Phillippe Aumont and J.C. Ramirez. Aumont went 1-6 with a 7.43 ERA in 11 starts with Double-A Reading before the Phillies demoted him to Class A Clearwater, where he is 2-3 with a 4.08 ERA in 13 appearances (seven starts). Ramirez is a combined 7-6 with a 4.65 ERA with Clearwater and Reading.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.