I haven't heard any specific rumors but it's hard to imagine the Padres keeping their lone All-Star Justin Upton past the trade deadline. He'll be a free agent at the end of the year and if the Padres trade him now to a contending team they may get some value that could improve the team sometime in the future. On the flip side they'd be losing Justin Upton for the second half of the season, which would be bad.
Upton says he'd like to finish the season in San Diego. Maybe that's the way he really feels and maybe not but I'd expect most players to say something similar about their current team.