The Washington Nationals officially announced the signing of free-agent pitcher Dan Haren to a one-year, $13 million contract on Friday. Haren, 32, joins a Nationals starting rotation that includes Stephen Strasburg, Jordan Zimmermann, Gio Gonzalez and Ross Detwiler. Haren was 12-13 with a 4.33 ERA for the Angels this past season, although he missed playing time with back and hip problems. The Angels declined Haren's 2013 option and bought him out for $3.5 million. The Angels had nearly traded him to the Cubs for Carlos Marmol, but that deal was canceled by the Cubs at the last moment.