Actually, the Bishop isn't the one who threw the Sister under the bus, the school in Charlotte and, as I understand it, those in the chain of command the Nun reports to in TN as well if it's true they'll no longer be letting here speak at "Catholic" schools.
Now Bishop Jugis has stated his position and we'll see how things go from here.
If you read the comments (at the source) of the story posted yesterday on the statement from Aquinas College, they quote the president of the college as saying there are fears for Sister Jane's personal safety. (That appears to be at least part of the reason for her sabbatical.)
I think Aquinas is trying to protect her, not "throwing her under the bus".