San Jose Earthquakes reached the MLS play-offs as Portland Timbers finished top of the west.
The Seattle Sounders sealed a place in the MLS play-offs with a 4-0 thrashing of Dallas.
A 3-0 win over the Vancouver Whitecaps saw the New York Red Bulls clinch a spot in the MLS play-offs.
After Kevin Doyle retired from football amid concerns about injury caused by concussions, Roy Keane suggested an alternative for players.
Justin Morrow scored a hat-trick as Toronto FC sealed the Shield by accounting for New York Red Bulls 4-2 on Saturday.
Led by ex-Barcelona and Argentina boss Gerardo Martino, Atlanta made sure of a postseason berth with four regular-season games remaining.
Toronto FC were shocked 2-1 at New England Revolution as they were denied their first Supporters' Shield in MLS on Saturday.
Portland Timbers star Diego Valeri set an MLS record, and Atlanta United did likewise in front of a crowd of 70,425.
A brace from Jozy Altidore helped Toronto to a win over the San Jose Earthquakes, sealing a spot in the MLS play-offs.
A goal from Bastian Schweinsteiger helped Chicago Fire edge past Montreal Impact in MLS.