Agent Drew Rosenhaus announced the move on his Twitter account and said Morgan's decision is final this time.
"Dan Morgan has informed the Saints that he has decided to retire due [to] continued injuries," Rosenhaus said. "Dan would like to thank the Saints for the chance to come back this year, but injuries would not let him continue his career. His decision [is] final and he will be moving on to focus on his restaurant business in Charlotte. Dan also wants to be able to spend more time with his wife and children."
Morgan retired last spring, only a few months after signing with the Saints. He sat out all of last season but decided in January that he wanted to return and was healthier than at any time since his rookie year in 2001. He had been working out with the Saints throughout the offseason and was viewed as a possible starter at weakside linebacker.
But Morgan's star-crossed career took a final hit Friday afternoon when he strained a calf muscle in a minicamp practice. Morgan was with Carolina from 2001 until 2007. Although he was spectacular at times, he was never able to stay healthy.
Morgan never played a full 16-game regular season as constant injuries, including at least five reported concussions, held him back.
Pat Yasinskas is the NFC South blogger for ESPN.com.