Sherrill, 32, currently has 20 saves and a 2.35 ERA, while striking out 35 and walking just 12 in 38.1 innings pitched.
It also might open the possibility of Sean Marshall returning to the Cubs' starting rotation, as he's been the lone lefty in the Cubs' pen most of this season. Marshall being available as a starter could impact the future of Rich Harden in Chicago as well. Harden has struggled, especially at home, for the better part of the last two months.
The addition of Sherrill would provide manager Lou Piniella much more flexibility at the end of games, with three potential shut down closers in his arsenal (with Carlos Marmol and Kevin Gregg being the other two).