The Brewers designated Irving Falu back in late June after he saw limited playing time and hit literally nothing (0 hits in 12 plate appearances). The Padres claimed him and he spent three weeks with them. Despite managing 3 whole hits in 20 plate appearances the Padres also designated Irving Falu leading to one of the more humorous events in recent memory. The Brewers have re-claimed Irving Falu. To make room for him on the 40-man roster they have designated Kevin Shackelford.
We probably don't need to go over Irving Falu much. We know he's a mediocre to poor utility player who can man second and third bases and fake shortstop in a pinch. He isn't going to hit well so he really is only insurance against an injury. Jeff Bianchi's shoulder was hurting before the All-Star break so perhaps he'll be heading to the DL soon? That's just a complete guess, I haven't heard that. There's also a solid chance Irving Falu plays the rest of the year out at Nashville and maybe gets a September call-up. In fact the Brewers immediately optioned him to AAA so far now at least we know Bianchi will stick around.
Kevin Shackelford was just added to the 40-man roster this year. Drafted in 2010, Shackelford has had a decent minor league career out of the bullpen. His best season was last year when he split the season between A+ and AA (combined 3.08 ERA) and then finished the year in the AFL (3.09 ERA). This year has been his worst season. He began in AA and got hit pretty hard. A stint where he pitched excellently in A+ may have straightened him out as he was promoted back to AA in July. There's a chance a team puts a claim on him. He's pretty far down on the Brewers bullpen depth chart so if does go to another team, it's not going to matter.