Melvin Gordon trade precedent: Another position
Although not a running back himself, Odell Beckham presents another case the Chargers could use as a baseline. A superstar in his own right, he was traded to the Browns just one year after receiving an extension from the Giants. His time in New York was famously known for big time plays and big time drama. Beckham Jr. seemed to be happy there, but the Giants front office ultimately decided to go in another direction. In return for the superstar receiver, the Browns sent the Giants safety Jabril Peppers, a 2019 first round pick (which the Giants used to draft former Clemson defensive tackle Dexter Lawrence) and a 2019 third-round pick (Old Dominon defensive end Oshane Ximenes).
The Chargers could follow this route and trade for a relatively young player at a position of need they like and then two early round draft picks to follow. Ultimately, the two keys here are how the Chargers value Gordon and how they value their ability to develop talent. In both the Beckham Jr. and Williams trades, each team was able to get three valuable assets in return that in theory should turn or could have turned into quality starters. Should they decide to go forward with the trade, there are plenty of teams that could use a player like Gordon that the Chargers could target.