The Cubs have officially announced the signing of Edwin Jackson.

Chicago agreed to terms with Jackson on Dec. 20. He will receive a four-year, $52 million contract. The deal includes an $8 million signing bonus with annual salaries of $11 million per year, according to a source.

Jackson, 29, was 10-11 with a 4.03 ERA in 31 starts with the Nationals in 2012.