May 18 12:36 PM PT1:36 PM MT2:36 PM CT3:36 PM ET19:36 GMT3:36 AM 北京时间12:36 PM MST2:36 PM EST2:36 PM CT23:36 UAE15:36 ET18:36 - San Francisco 49ers star defensive lineman Justin Smith is retiring. Analysis: Smith played 14 seasons in the NFL after being drafted in the first round by Cincinnati in 2001. After seven seasons with the Bengals, he signed as a free agent in San Francisco and had his best success in seven years with the 49ers. He was a defensive stalwart on a team that made three straight NFC championship games and played in one Super Bowl. Smith is a two-time All-Pro and a five-time Pro Bowler.