From Fact Sheet (
https://assets-ssl.usta.com/assets/1/15/2016_australian_open_wild_card_men_fact_sheet_20151005.pdf):
The wild card will be awarded to the American player with the highest total of cumulative singles
main draw ATP ranking points from the events listed below:
• Players’ singles results from the best two (2) events will be used and combined to calculate the point total.
• In the event of a
tie, the player with the best ATP singles
ranking in the published ATP rankings of Monday,
November 23, 2015 will be awarded the wild card.
• Players must compete in the singles event of at least one of the three events listed below to be considered for the wild card.
• Should the player with the highest total of cumulative singles ATP points become a Direct Acceptance into the Australian Open, the next qualified American player with the highest cumulative total of singles ATP points will be awarded the wild card (ties will be broken as described above).
• In the event that issues arise that are not covered by these rules, USTA Player Development will be the final arbiter.
According to
Live ATP Rankings, Rubin has 138 ranking points, Thompson will have 135 if he wins in Champaign