The Giants have signed left-hander Dontrelle Willis to a minor-league contract, reports John Shea of the San Francisco Chronicle. It's unclear if he received an invitation to spring training as well.

Willis, 31, has not pitched in MLB since 2011 with the Reds. He went 1-6 with a 5.00 ERA and 1.54 K/BB in 75 2/3 innings across 13 starts that year. Willis has not been an effective big leaguer since going 12-12 with a 3.87 ERA (122 ERA+) in 201 1/3 innings for the 2006 Marlins, a year before being traded to the Tigers along with Miguel Cabrera.

After flirting with retirement a few years ago, Willis has been bouncing around the minors and independent leagues. He made 14 starts with the independent Long Island Ducks last summer before hooking on with the Angels and throwing 21 ineffective innings for their Triple-A affiliate.