I accidentally clicked "retain rights" on one of my second round draft picks. He would not come up in the Free Agent menu during the season, so I couldn't figure out how to sign him. I just got a notification in the following off season that I can exercise, ignore, or give up the rights to said player. I want to sign him, but he doesn't appear on my team contracts page.

How do I exercise the rights and get this guy signed to my team? During free agency? Right now he's just languishing as a free agent and lost a year of G League development.