Twitter has made learning about upcoming roster moves a lot easier. For example:
Jim Adduci will presumably be added to the 40 man roster when rosters expand on September 1. An outfielder who can play all three outfield positions, Adduci was a 42nd round draft pick of the Florida Marlins in the 2003 draft. The Marlins traded him to the Cubs for Zach McCormick prior to the 2007 season. Adduci stayed in the Cubs system until after the 2012 season, when he signed with the Rangers as a minor league free agent.
Adduci, 28, turned heads in spring training, generating some buzz as someone who could potentially be in the mix for an outfield job if the Rangers needed someone for depth, and put up a .298/.381/.463 line this season for Round Rock. Jason Cole had a writeup on Adduci over at BP earlier this week, and Adduci sounds like a guy who doesn't have any one really strong tool, but does a lot of things well enough that he could possibly provide value as a backup outfielder. The Rangers will likely keep him on the 40 man roster this offseason, and some Googling seems to suggest that Adduci has two options remaining, so they could stash him in the minors next season as depth.
The Rangers are also going to be activating Neftali Feliz from the 60 day disabled list when rosters expand, so with Feliz and Adduci, the team will need to create a 40 man roster spot. Joe Benson, who is out of options after the season, and who hasn't hit since being claimed on waivers from Minnesota earlier this season, would seem to be the most likely casualty. UPDATE -- It was pointed out in the comments that Roman Mendez, who is out for the year, is not yet on the 60 day d.l. Putting Mendez on the 60 day d.l. would be the easiest way to create a spot.
The Rangers would need a second roster spot if they opt to activate Michael Kirkman from the 60 day disabled list as well. Activating Kirkman could result in someone like Chris McGuiness or Joey Butler seeing their roster spot being put in jeopardy. Alternatively, one of those players, or someone like Justin Miller, could be placed on the 60 day d.l. to open up a roster spot.