Thompson was optioned to Triple-A Lehigh Valley after Sunday's game against the Mets.
He was not used out of the bullpen after being recalled earlier in the week, and apparently the Phillies no longer need his services. Thompson's outlook is not promising, as he has been unsuccessful as a starter at Triple-A and as a big-league reliever. His control has been particularly poor at both stops this season (13 walks in 22.2 innings).