Can FC Dallas hang on to win the Supporters' Shield without Mauro Diaz? Sunday is Decision Day in Major League Soccer, as the final 10 games of the regular season kick off simultaneously at 4 p.m. ET. A major trophy is at stake, as is a knockout-round bye in the East, and four playoff spots are not yet determined, setting the proverbial stage for plenty of final-day drama. Here's what remains up for grabs, the scenarios for various clinchings and the likelihood of each event happening, courtesy of ESPN's Soccer Power Index (SPI): ...