Complex sentence: In September 2014, Weigel left "Slate" in preparation for a new job at Bloomberg Politics; however, after only nine months at Bloomberg Politics, Weigel returned to "The Washington Post" on 20 July 2015.
Split into simpler sentences: In September 2014, Weigel left "Slate" in preparation for a new job at Bloomberg Politics. After only nine months at Bloomberg Politics, Weigel returned to "The Washington Post" on 20 July 2015.