Per a variety of folks on twitter, Darren Oliver has signed a one year contract with the Toronto Blue Jays, with a club option for 2013.
Oliver had a very good season out of the bullpen for Texas in 2011, and the Rangers reportedly were interested in bringing him back for 2012. That said, he also had a couple of memorable games where he blew leads, and generally was less successful overall last season in high leverage situations, which resulted in a certain segment of the fan base proclaiming that he was terrible and shouldn't even have a roster spot, despite his excellent numbers.
The Rangers have generally carried at least two lefties in the bullpen, but currently don't have anyone definitively in place for a lefty role in the pen for 2012. Texas is reportedly interested in bringing back Mike Gonzalez, acquired from the Orioles for Pedro Strop last August, and Michael Kirkman will probably have a chance at earning a bullpen job.