Buuxi weedhan soo socota: Jansen wuxuu ku soo laabtay Horyaalka Xeebta Baasifigga isagoo ah tababare-ciyaaryahan la leh Seattle (1955 iyo 1957) iyo Portland (1958<unk>60). Kadib wicitaan ka yimid saaxiibkii hore ee kooxda Alvin Dark, Jansen wuxuu ku soo laabtay Horyaalka Sare isagoo tababare u ah San Francisco Giants sanadkii, iyadoo Dark uu ahaa maamule. Jansen wuxuu sii ahaaday tababare 11 xilli ciyaareed, wuxuuna gacan ka geystay horumarinta Hall-of-Famers Juan Marichal iyo Gaylord Perry. Intii uu xilka hayay, kooxda Giants waxay ka soo muuqatay 1962 World Series iyo
Horyaalkii Horyaalka Qaranka ee 1971. Kadib wuxuu u wareegay shaqadiisii ugu dambeysay ee tababarka MLB, isagoo u adeegsanayay Chicago Cubs sanadkii 1973, isagoo u shaqeynayay maareeyihiisii hore ee Giants, Leo Durocher, ka dibna saaxiibkii hore ee Whitey Lockman.