This is standard procedure after the non-waiver Trade Deadline passes, and not totally unexpected. It's unlikely that Lee (2-6, 3.73 ERA) will be claimed because he's owed $25 million in each of the 2013, 2014 and 2015 seasons, with a $27.5 million option in 2016 that vests if he throws 200 innings in 2015, or 400 innings in 2014 and 2015 combined.
Even if Lee is claimed, the Phillies have the option of pulling him back. If he clears waivers, it gives the Phillies the option to trade him. There were reports circulating in the days leading to Tuesday's non-waiver Trade Deadline that the former Cy Young Award winner was on the trading block, but Lee said after his start on Tuesday that general manager Ruben Amaro Jr. told him those were just rumors.
"Ruben did tell me that some teams proposed some stuff to him, but nothing that ever made even close to sense for the Phillies," Lee said then.