Phillips signed with the Lions during the summer as an undrafted free agent and played his way onto the team for good, earning a spot on the 53-man roster after having an impressive preseason. With Louis Delmas out for much of the preseason, Phillips got a chance to show what he's got and played very well, flying around the field and making plays.
Evidently the Lions haven't been quite as impressed with him during the regular season, because today they brought back Wesley, a defensive back who was released during the final round of roster cuts. I guess at this point they were ready for a change, and unfortunately that meant Phillips being let go. It will be interesting to see if he is kept around on the practice squad, assuming he clears waivers and wants to stay with the team.
UPDATE: According to Dave Birkett, the Lions will sign Phillips to the practice squad if he clears waivers.