Closer Jonathan Papelbon was put on the 15-day DL by the Washington Nationals because of a right intercostal strain suffered while warming up Sunday, when he pitched one inning against the Philadelphia Phillies. He gave up a go-ahead home run to Maikel Franco before Washington rallied for a 5-4 victory. ... Left-hander Brian Matusz was signed by the Chicago Cubs to a minor league contract. Matusz was 27-41 with a 4.85 earned-run average over parts of eight seasons with the Baltimore Orioles. He was traded last month to the Atlanta Braves, who released him recently.