Hey Jeff, i used Enhanced Text Widget to create the the sidebar link
inside i put the following code:
[url=http://justpaste.it/imon]justpaste.it/imon[/url] (code doesnt seem to like being pasted.
(I added some text to the code in an else statement, shows up when edit link disappears)
You should also be able to put the code in the card-single.php template and it will display.
Not sure if this will resolve your error. Hope it helps a little.