Men's world No 1 Novak Djokovic, 2018 champion Naomi Osaka and 23-times grand slam champion Serena Williams are also not competing at the competition.
Raducanu has won all 16 sets she has contested through eight matches in New York — three during the qualifying rounds and another five in the main draw.
Aryna Sabalenka geared up for next week's US Open by climbing to second place in the WTA rankings published, nudging Naomi Osaka down to third.
Sabalenka saved all eight break points she faced in the first set — including four at 5-5 — and then converted her first when Pliskova double-faulted on set point.
The stage is set for the women's Wimbledon semi-finals on Thursday with three of the contenders new to the experience.
Two weeks after nearly withdrawing from the tournament because of a muscle injury, Sabalenka was standing on center court with the winner's trophy in her hands on Saturday.
The five-time Grand Slam winner came from behind to beat 19-year-old Aryna Sabalenka 7-5, 7-6 (10/8) in Tianjin Open Final.