The LA Galaxy are set to unveil Steven Gerrard on Saturday, but sources tell Goal USA he isn't the only star midfielder on his way to the reigning MLS champions.

When the LA Galaxy unveil English star midfielder Steven Gerrard as the club's newest star signing on Saturday, his arrival will give the LA Galaxy the current MLS maximum of three designated players. But that doesn't mean the club doesn't have another star signing in the works.

Spanish publication El Periodico Mediterraneo reported on Tuesday that La Liga side Villarreal is in advanced discussions with the Galaxy regarding a $7.7 million transfer of Mexican national team star Giovani dos Santos. Multiple sources have confirmed to Goal USA that a transfer for Dos Santos to join the Galaxy is indeed in the works, and its completion will be aided by impending changes to the current MLS salary cap and roster guidelines.

Sources tell Goal USA that MLS owners are ready to ratify changes to the current salary cap rules to create a core player roster spot that will effectively work as a fourth designated player spot for any teams currently using all three slots.

The Galaxy currently boast reigning MLS MVP Robbie Keane and U.S. national team defender Omar Gonzalez as DPs, with Gerrard joining as the third this weekend. Dos Santos, who is currently with the Mexican national team preparing for the CONCACAF Gold Cup, would not join the team until August, by which time MLS would be expected to have implemented its salary cap slot changes.

One source within MLS confirmed to Goal USA that the adoption of the core player roster slot is a "safe bet" to be approved this summer, thus clearing the way for the Dos Santos transfer. It remains unclear whether MLS will foot the bill for Dos Santos' transfer the way it did with Clint Dempsey's move from Tottenham to Seattle, or if the Galaxy are going to pay for the transfer and the sizable salary Dos Santos will be paid.

Dos Santos has been linked to the Galaxy for some time, though he now appears ready to a move that standout Mexicans Cuauhtemoc Blanco and Rafa Marquez made before him.

In Dos Santos, the Galaxy would be adding the Mexican star the club has craved in order to help secure a larger segment of the soccer fanbase in the greater Los Angeles area, particularly with the looming arrival of a second MLS team in the market in 2018.

If the Galaxy do land Dos Santos with the help of the core player slot, they won't be the only team doing essentially boasting four DPs. New York City FC is preparing to add Frank Lampard and Andrea Pirlo to David Villa as three designated players. Mix Diskerud was believed to be a player the club would earmark for its core player rule, but having already paid down his salary slot this season, NYCFC could be using the core player slot to help squeeze in the arrival of Spanish international Andoni Iraola, a highly-regarded defender who was a regular starter wiith Athletic Bilbao.

The Sounders and Toronto FC are also currently featuring three DPs, meaning they too could take advantage of the newly-created core player slot once it is approved.