Partick Thistle have terminated the contract of Jordan McMillan following an internal investigation.
Lionel Messi will end his career at Barcelona, Chelsea manager Jose Mourinho believes.
The 33-year-old could make his debut for the Owls on Saturday against Birmingham after signing a deal that runs until mid-January 2014.
The former Republic of Ireland midfielder will be reunited with Wednesday manager Dave Jones, the man who took him to Cardiff in 2006 where McPhail has spent the last six years.
McPhail made 190 appearances for the Welsh side, scoring three goals, before he was released at the end of last season.