Weir, from Bright's Grove, Ont., got one of six spots that had been set aside to accommodate anyone who moved into the top 60 in the world ranking published Monday. Kyle Stanley, who finished third at the Memorial, was at No. 60. He was the only one who qualified from the latest world ranking.
After that, five players who were alternates at the 36-hole sectional qualifying spots filled the 156-man field.
Weir lost in a playoff at the main Ohio qualifier and was first alternate. Also getting into the U.S. Open as a qualifying alternate were Calgary native Ryan Yip, Ryan Palmer, Rikard Karlberg and Harold Varner III.
Weir has not played in the U.S. Open since 2010.