I'm not really down on Sosa for the right role, just not sure the right role exists for him here. And he's 0.1 WAR in 73 games this year whereas he was 0.8 WAR in just 25 last year (and 1.4 in 78 between his two teams).
At 3B he and Bohm are both RHBs and, at least this season, Sosa's defensive upgrade is not as dramatic as it should be (at least not when he hits the way he does). At SS he and Turner are both RHBs though Sosa probably wouldn't be much of a downgrade lately. And Stott doesn't really need to be sat against LHP that often.
Thus, a negligible/scrub utility IF wouldn't make the team that much worse if packaging Sosa in a trade made the team better. (I don't really mean Torreyes specifically, but someone younger). Of course I don't really expect that to happen at the deadline.
And I don't really think acquiring a RH OF is going to affect his playing time (i.e. Harper would start to play 1B every day regardless, and therefore Bohm would play 3B almost every day).
At this point I think Clemens could probably match Sosa's production, he put up 0 WAR and hit 4 HRs in half as many ABs and would hit RHP. Technically he can also play SS (but so can Stott) if they needed one.