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Team USA will begin its quest to repeat as World Baseball Classic champions on Saturday night, opening pool play against Great Britain. (Click here to read why we're bearish on the Americans' title chances.) Longtime St. Louis Cardinals ace Adam Wainwright will get the nod in the opener, but the bigger assignment -- Sunday night's start against Mexico -- will belong to San Diego Padres righty Nick Martinez, according to Bob Nightengale of USA Today.

Martinez, who was named to the USA roster after Los Angeles Dodgers lefty Clayton Kershaw had to be removed earlier in the spring, spent most of last season pitching in relief. He performed well, amassing a 3.47 ERA (108 ERA+) and a 2.32 strikeout-to-walk ratio across 47 games, including 10 starts. The Padres have tasked him with moving to the rotation this season, meaning that Sunday's outing will be important to him for reasons other than the obvious.

Earlier this spring, Martinez spoke about how proud he was to suit up for the Americans. "Given my family's history, coming to this country looking for opportunity ... having their son represent this country is an honor for us," he told Jon Morosi as part of MLB Network's WBC coverage

The rest of the American roster is yet to be announced, but Nightengale had previously tweeted that Chicago White Sox right-hander Lance Lynn was expected to get the nod on Monday against Canada, while Cardinals righty Miles Mikolas was projected to start on Wednesday against Colombia. 

Mexico, for its part, has not announced a starter yet for Sunday's game. Taijuan Walker (Phillies), Patrick Sandoval (Angels), and José Urquidy (Astros) are all candidates who are expected to be part of MLB rotations. Mexico used its best starter, Dodgers lefty Julio Urías, on Saturday in a loss against Colombia.