York9 released some renders and information on stadiums they'll be using for the next few seasons.
http://canpl.ca/video/york-9-fc-unve...019-and-beyond
York Alumni Field (early 2019-mid 2019)
York Lions Stadium (mid-2019 onwards)
York9 are planning on playing out of York Lions Stadium for 2-3 years with an eye at building a 12-15K stadium.
York Lions Stadium is going to be renovated in the first half of 2019 (taking out grass and putting in turf so the stadium can be used by soccer, rugby, etc.) so York9 have to play out of Alumni until that is completed. The Ontario Arrows of Major League Rugby will also be using York Lions Stadium next year when they start their first season.
If you thought the Toronto sports markets was diluted enough it's going to be even more diluted next year.
