Each of these 10 players has also had a profound impact on the growth of both MLS and professional soccer in the U.S.
6. Kaka (Orlando City SC, 2015): He's the first former world player of the year to join MLS, though Kaka's best days were clearly behind him when he signed with expansion Orlando at age 32. But his presence helped Orlando draw a league-record 62,510 fans for its debut, and the team is averaging more than 34,000 through 10 home games.
7. Steven Gerrard (Galaxy, 2015): One of the iconic players of his generation, the former Liverpool and English national team star had never played a club game in anything but a Liverpool shirt before making his Galaxy debut last week. He's 35, and his strength and stamina could be an issue in MLS.
10. Sebastian Giovinco (Toronto FC, 2015): Like Dos Santos, the 28-year-old Giovinco jumped from Europe — in Giovinco's case, Italian club Parma — to MLS in the prime of his career, signing a league-record five-year, $35-million deal. And so far he's proved a bargain since he leads the league in shots and is second in goals.