"I think I knew in my heart I was done after last season," Modano said. "I had a harder time coming to grips with it than I thought I would. Part of me wanted to play it out and see if anybody had called in July. When that didn't happen, I figured that's pretty much it.
"I wasn't working out much. I wasn't skating. There wasn't motivation to do much. I was traveling and at that point, I said, 'Let's pick a day here and get the thing on the calendar.'"
Modano did tell the Associated Press on Wednesday that he recently declined a chance to continue his career with the Vancouver Canucks.
A news conference announcing his retirement is slated for Friday morning at the Ritz-Carlton in Dallas.
Modano, who was drafted by the Stars when they were still known as the Minnesota North Stars, spent all of one season with the franchise. Modano helped lead the Stars to their 1999 Stanley Cup victory.
Modano holds various NHL records including goals and points by an American-born player. Modano also has the most games, points, goals and assists records for the Stars -- in both the regular season and playoffs.