Wei-Yin Chen

On January 30, 2020, Chen signed a minor league contract with the Seattle Mariners.

Chen was designated for assignment on November 20, 2019. He was released and became a free agent on November 27.

On January 13, 2016, Chen agreed to a five-year contract worth US$80 million with the Miami Marlins. Chen was named the starting pitcher for the opening day of the 2016 season, becoming the second Taiwanese pitcher to make a start on opening day since Chien-Ming Wang in 2008. On January 25, 2017, Chen was announced as the cover athlete for the Taiwanese version of MLB The Show 17. In his first season as a Marlin, Chen went 5-5 in 22 starts after spending some time on the disabled list with an injury. He posted the worst ERA of his career, finishing at 4.96 in 123 innings.

On June 26, 2015, Chen became the second Taiwanese-born player to have 100 career starts in the major leagues (after Chien-Ming Wang), allowing two runs and striking out five over six innings in a no decision against the Cleveland Indians. Despite only recording a 4–5 record at the break, Chen pitched to a 2.78 ERA and a 1.09 WHIP, along with 90 strikeouts in 110 innings over the first half of the season. Chen finished the season with an 11–8 record and a career-best 3.34 ERA over ​191  ⁄3 innings pitched.

Coming out of spring training, Chen won the number two spot in the Orioles' starting rotation behind Jason Hammel. Chen set a goal to throw 200 innings on the season. In his first three starts, he lacked run support and went 0–2 despite posting a 4.00 ERA. On May 15, 2013, the Orioles placed Chen on the disabled list, his first-ever stint there, with an injury to his right oblique. In his return from the disabled list on July 10, 2013, Chen pitched seven innings in a matchup against the Texas Rangers striking out four and allowing three hits, earning the win. Overall in 2013, Chen finished 7–7 with a 4.07 ERA in 23 starts. During the 2013 off-season, Chen underwent knee surgery to remove bone spurs.

Chen is an "extreme flyball pitcher", at one point having an HR/9 innings of 1.3, way above MLB average. Chen pitches from a three-quarters arm slot and throws a four-seam fastball averaging 91–92 mph (tops out at 95–96 mph). In addition, he throws a two-seamer, a slider, a changeup, and an occasional curveball. Since he previously pitched in Japan where he started on five days rest rather than four, with the Orioles he initially had durability issues and was 0–4 in his last seven starts in 2012. Chen has been described as a legitimate middle-of-the-rotation starter. An opposing scout said, "I watched Wei-Yin Chen and swore I was watching Tom Glavine. He has such an effortless delivery and an above-average change up, and knows how to pitch inside."

After the 2011 season, Chen signed as an international free agent with the Baltimore Orioles. Chen was the first Taiwanese player ever signed by the Orioles. He made his MLB debut on April 10, 2012 against the New York Yankees in Baltimore. The game was broadcast live on national television in native Taiwan, and Chen totaled 5​⁄3 innings and gave up two earned runs striking out six in a no-decision that the Orioles would later go on to lose in extra innings. In total, Chen finished the season leading the team with 32 starts during which he totaled 12 wins and 11 losses and posted an ERA of 4.02 in 192.2 innings pitched. In 2012, Chen was "the only constant in the (Orioles) rotation" and was consistent throughout the year. Chen finished fourth in the AL for Rookie of the Year voting.

In 2012, Chen started a baseball scholarship program for Taiwanese students, contributing funds based on statistical milestones reached per season. He expanded the charity's efforts in 2015, to cover animal protection and children's welfare.

He was a pitcher for the Chunichi Dragons in Nippon Professional Baseball (NPB) from 2004 through 2011. Chen had Tommy John surgery at the end of 2006 season. His best season in Japan came in 2009 when he posted a 1.54 earned run average (ERA) to lead the league. When he came out of the Nippon League, FanGraphs described him as being an extreme control pitcher with poor velocity. A clause implemented into his contract with Chunichi allowed him to opt out after the 2011 season at age 26.

Chen played for the Chinese Taipei National Team in the 2004 and 2008 Olympic Games.

Wei-Yin Chen (Chinese: 陳偉殷 ; pinyin: Chén Wěiyīn ; born July 21, 1985) is a Taiwanese professional baseball pitcher in the Seattle Mariners organization. He previously played in the Major League Baseball (MLB) for the Baltimore Orioles and Miami Marlins, and in the Nippon Professional Baseball (NPB) for the Chunichi Dragons.