Saunders will play for Canada, Perez for Mexico and Liddi for Italy, with all three nations competing in Group D of the opening round in Arizona from March 7-10.
"I've worn a Canadian jersey since I was 12, up until the 2008 in the Olympics. I haven't been able to put one on since," said Saunders, who watched the 2009 WBC with friends in Arizona while he recovered from shoulder surgery.
"I'm really looking forward to it. I'm excited, I'm honored and it's always a very proud moment when you get to wear your country's name across your chest."
Perez, who is from Culiacan, will be pitching in his third WBC. Family and friends will either come to see him in Arizona or watch on TV.
"It's your country, right? You have the duty to report to them and put on the uniform, and it's a lot of pride playing for the country of my birth," Perez said. "It's a beautiful thing when you hear your national anthem in another country."
The 24-year-old Liddi was 3 for 8 with two RBIs in the 2009 WBC. When he homered against Cleveland in 2011, he became the first player born in Italy to go deep in the major leagues since Detroit's Reno Bertoia in 1961.
"Every guy has more experience so it should be better, and we know what to expect this time," Liddi said.
Notes: The Mariners traded 1B Mike Carp to Boston for a player to be named or cash. Carp was designated for assignment on Feb. 12 to make room on the 40-man roster for pitcher Joe Saunders. ... RHP Felix Hernandez threw his first bullpen session of spring training and made 33 pitches. Manager Eric Wedge said Hernandez threw mainly fastballs and changeups, and said he isn't worried about any injuries. ... Hernandez received a special gift from teammate Franklin Gutierrez, a bedazzled rendering of Hernandez's celebration of his perfect game last season. ...
Wednesday's outdoor workout was washed out by rain ... RHP Hector Noesi is to start for Seattle on Friday's annual charity game against complex partner San Diego. RHP Blake Beavan is the scheduled starter Saturday and RHP Erasmo Ramirez on Sunday, also against the Padres.