Taiwan-born southpaw Wei-Yin Chen makes his fourth major- league start for Baltimore tonight when the Orioles host the Oakland Athletics in the middle game of three straight at Camden Yards.

The 26-year-old came to the United States and joined the Orioles after signing a three-year deal that will pay him $3.072 million this season, $3.572 million next season and $4.072 million in 2014.

The team has an option for 2015 that includes a $4.75 million salary or a $372,000 buyout.

Chen has pitched 17 1/3 innings in three starts with Baltimore and scored a win in his lone decision while surrendering 18 hits and seven runs with 15 strikeouts and six walks.

He's permitted a .261 opposition batting average.

Oakland counters with California-born righty Tyson Ross, who turned 25 years old last week and faces Baltimore for the sixth time.

The 6-foot-6, 230-pounder was 1-4 in 26 appearances with the Athletics as a rookie in 2010, split six decisions in nine games in 2011 and won his initial decision of 2012 against Cleveland on his birthday.

Ross allowed a run on four hits in 6 2/3 innings to beat the Indians, five days after going six innings and allowing two runs against the Los Angeles Angels in Oakland's 5-3 win.

Ross is 0-1 in his previous five meetings with the Orioles with an 11.12 earned run average in 5 2/3 innings.

On Friday, Eric Sogard hit a two-run home run, while Brandon McCarthy earned his first victory of the season as the Athletics took a 5-2 decision.

McCarthy (1-3) allowed just two runs on five hits and three walks over seven innings in the start. Ryan Cook struck out four Orioles in the eighth after Adam Jones reached on a wild pitch and Grant Balfour worked around a leadoff walk in the ninth to earn his sixth save of the season.

Josh Reddick hit a solo homer and drove in two, while Kurt Suzuki knocked in a run and scored once for Oakland, which has won three straight.

Jake Arrieta (1-2) was touched for four runs on four hits and two walks over his 5 2/3 innings in his start for Baltimore. Jones and Nick Markakis each had an RBI in the loss as Baltimore saw its four-game win streak come to an end.

The A's won five of nine versus the Orioles last season, but lost all three games in Baltimore.