i think this is incorrect, I am 99% sure they qualified when they won the shield.
For the United States, four teams qualify for the CONCACAF Champions League, three through the Major League Soccer (MLS) season and one through its domestic cup competition:
- The champions of the MLS Cup, the championship match of the MLS Cup Playoffs
- The champions of the Supporters' Shield, awarded to the team with the best MLS regular season record
- The MLS regular season champions of either the Eastern Conference or Western Conference which are not the Supporters' Shield champions
- The champions of the U.S. Open Cup