The 26-year-old was never going to pull a Le'Veon Bell and hold out the entire season. Gordon needs to report at some point to earn an accrued season towards free agency; otherwise his $5.6 million contract will toll.
Whether he plays the end of the year with the Chargers or another club remains to be seen. The team granted Gordon's agents permission to seek a trade of the running back. Nothing has materialized as of yet and barring a big-name injury to a playoff team it's skeptical one might pop up. Coupling the Chargers' trade demands and Gordon's contract desires could make a deal tough to come by.
With Austin Ekeler and Justin Jackson performing well, Gordon's leverage with the Chargers has shrunk, if anything, since the season started. Barring injuries in L.A., a Chargers implosion, or disaster striking elsewhere, that leverage might not ever rise to the level Gordon would need it to get what he wants in 2019.
Gordon knows his holdout has an expiration date at some point this season. It always has. Until then, he'll train and get ready for his eventual report date down the road.