As seen above, TNA released an exclusive teaser for tomorrow's live Impact Wrestling episode to Rolling Stone. They are teasing that "one of wrestling's hottest free agents" will debut with TNA tomorrow night.
Based on music used in the teaser and the "doing things his way" line, it appears this could be for Damien Sandow's TNA debut. Sandow was released from WWE back in early May.
UPDATE: Sandow tweeted the following, apparently confirming that it's him debuting: