I'm pretty sure Johnson has pulled out last minute, McLaughlin isn't with the squad so it was a choice between Kelly who looked way off the pace last week, Flanno or move one of Henderson or Toure last minute which would probably disrupt the team as I'm sure they've been preparing and training for this all week.
You don't really want to have to chop and change your team completely at the very last minute so putting Flanagan in for Johnson is probably the least disruptive move Rodgers could make for the team.
Hopefully he does well, just wanted to play Devil's advocate and apply a bit of sense to the situation rather than slate Flanno and Rodgers!