As of August 2014, there are many indications that both Thierry Henry & Landon will be retiring at the end of this MLS season.
Landon Donovan carried the weight of the league and sport on his shoulders for years and has performed at a high level for the US Men's National Team throughout his career. He is often mentioned as the greatest American player ever.
Thierry Henry for his part is widely considered to be one of the best footballers of all time. He achieved legendary status at the club level and also for France in international competition.
The presence of these players in MLS would greatly benefit US soccer as a whole.
The retirement plans of these two players present a clear and present danger to the growth of soccer in the USA.