On a snowy afternoon in downtown Chicago, Shōta Imanaga pulled on a Cubs cap and a crisp, pinstriped No. 18 jersey in the middle of a hotel ballroom. Imanaga was formally introduced by the Cubs on Friday, a day after he finalized a $53 million, four-year contract. Nicknamed “The Throwing Philosopher,” he went 7-4 with a 2.80 ERA in 22 starts last season with the Yokohama BayStars of Japan’s Central League, finishing with 174 strikeouts and 24 walks in 148 innings.