Swiatek returns to WTA hardcourts at Toronto
The Polish world number one, who collected six titles this season before her 37-match win streak was ended by Alize Cornet at Wimbledon, has a limited history at the Canadian event.
She previously played in 2019, losing as a qualifier in the third round to Naomi Osaka.
Swiatek last competed on cement on April 4 when she won the Miami Masters title.
The first of back-to-back pre-US Open tests in August for two-time Roland Garros champion Swiatek will be followed by the Cincinnati Masters with a preparation week to spare before the August 29 start of the Grand Slam in New York.
She will play her first match against the winner from American Shelby Rogers and 19th-ranked Veronika Kudermetova.
Second in the field will be Estonian Anett Kontaveit, beaten in the first round here last season.
Reigning US Open champion Emma Raducanu, seeded ninth, begins against tournament holder Camila Giorgi, who won the title a year ago over Czech Karolina Pliskova.
Raducanu this week reached the Washington quarter-finals and has been controversially engaged in a coaching trial with former Russian player Dmitry Tursunov.
The top quarter of the draw could be a minefield for Swiatek, with potential rivals including fifth-seeded Wimbledon finalist Ons Jabeur.
The Tunisian is one of a group of other threats in the quarter.
Others include Greek third seed Maria Sakkari, former number one Garbine Muguruza of Spain, 13th-seeded US Open finalist Leylah Fernandez, Olympic gold medallist Belinda Bencic of Switzerland and double Grand Slam winner Victoria Azarenka.
Lurking as a wild card entry in the top quarter is Serena Williams -- the winner in 2001, 2011 and 2013 who last played in Canada three years ago when she lost the final to Bianca Andreescu.
The 54th-ranked Andreesu, whose career since winning the US Open in 2019 has been beset by injury, opens here in the first round against 11th seed Daria Kasatkina.
Williams starts with a qualifier and then could face Bencic or Azarenka and a quarter-final with Swiatek remains a possibility.
Sister Venus Williams, 42, was also handed a wild card, playing Swiss Jil Teichman in the first round with the winner to get Kontaveit.
Wimbledon champion Elena Rybakin will be looking for her first win since taking the title at the All England Club as she takes on a qualifier in the first round.