Bad weather over the weekend caused delays that have backed up play at Sea Island Golf Club. John McClure was 1-up through 12 in his match against Charlie Stevens when play was called on Tuesday. Josh Dennis and Mark Thompson were all square through 17.
The two remaining matches will resume at 7:45 a.m. (et) on Wednesday.
Wilson had his first-round match suspended due to darkness on Monday and returned to the course Tuesday morning to move into the second round. The 41- year-old continued his marathon day with a 4 & 3 win over Danny Gurley before dusting McCuaig to reach the quarterfinals.
Wright Waddell won the par-5 15th with a birdie to take a 1-up lead over Michael Turner and held on to win his match for a spot in the next round.
Austin Eaton III defeated Tim Hogarth, 2 & 1, in his third-round match and will face Wilson in the quarterfinals. Kevin Marsh, who knocked off Trip Kuehne earlier in the second round, ousted Roger Hoit, 2 & 1, to advance to the quarterfinal matches.
Richie Taylor outlasted Patrick Carter, 4 & 3, while William Johnson took 19 holes to defeat Steven Irwin.
The quarterfinal and semifinal matches are scheduled for Wednesday following the completion of the third round. The 36-hole final will be held on Thursday.
The U.S. Mid-Amateur is one of 13 national championships conducted annually by the United States Golf Association, 10 of which are strictly for amateurs.