While there are obvious sellers, there is the teams that go into the All-Star break in-limbo, in which a good or bad run could make the difference in buying or selling, as silly as it sounds.
What will make this year interesting is the hard deadline for trades. Once July 31st comes and goes, no more trades.
The Twins will makes moves, they didn't clear out space on their 40 man for nothing. It probably won't be until the end of the week before we see it.