Lee is the highest-paid player in baseball through next year in terms of guarantee (about $48 million), and with him back for only two so-so (at best) starts after two months off with an elbow issue, they would prsumably have to pay a fair amount of his contract to do a trade.
One team that's looking for a starting pitcher is the Cardinals, but they would need quite a bit of Lee's salary paid down to consider such a deal, as they pay ace Adam Wainwright less than $20 million per season. The Dodgers have shown interest in Lee in the past.
It's very likely a Lee deal could occur in August since there's no reason to believe anyone would claim him on waivers.
The Phillies still seem to have little interest in trading Lee's rotation mate Cole Hamels. One Phillies person sugested as much, saying, "Hamels isn't going anywhere."