Clinton-Dix inked a pretty big 1-year deal with the Cowboys this offseason, getting $2.25 MIL guaranteed ... with the expectation the former first-round pick would be a key player for the defense.

But, after just a month of practices ... the Cowboys decided to part ways with the guy on Thursday -- and it's left a GLARING hole on their roster that some believe Thomas could easily fill.

Remember, the Baltimore Ravens just fired Thomas a week ago after a training camp fight with a teammate ... and the Cowboys have been linked to him HEAVILY in the past.

But, Dallas has been coy about its interest in Thomas over the past few days ... with neither Jerry Jones nor head coach Mike McCarthy explicitly expressing a desire to sign the guy.

But, with the team down to just 3 somewhat proven commodities at the safety position ... Earl HAS to look appealing right about now to Dallas brass.

So, could Earl have a star on his helmet by the NFL's opening weekend next week???