MassLive.com's Chris Cotillo first reported the news.
Per ESPN's Jeff Passan, Morrison and the Yankees agreed to a deal that will pay him $1 million if he makes it to the majors. Morrison also has the right to opt out by July 1.
Morrison, 31, played for the Minnesota Twins last season. The Twins declined his 2019 option after he hit just .186 with 15 home runs and 39 RBI in 95 games.
With first baseman Greg Bird on the 10-day injured list due to a plantar fascia tear in his left foot, Morrison could potentially serve as his replacement as a power-hitting lefty at first base.
While Morrison struggled mightily last season, he had a career year in 2017. As a member of the Tampa Bay Rays, he hit .246 with career highs of 38 home runs and 85 RBI.
If he can regain that form and make the big league roster, he has a chance to do some damage as a power hitter at Yankee Stadium due to the short porch in right field.
Morrison's signing could stir up some controversy among Yankees fans, though, based on comments he has made in recent years. When he was passed over for the 2017 Home Run Derby in favor of Yankees catcher Gary Sanchez, Morrison was publicly critical of Major League Baseball.
Sanchez had just 14 home runs at the time due to injury, while Morrison had 24. As a result, Morrison said, "Gary shouldn't be there. Gary's a great player, but he shouldn't be in the Home Run Derby. ... I remember when I had 14 home runs. That was a month and a half ago."
And as a member of the Twins last season, Morrison was critical of Yankees fans, per Mike Berardino of the Pioneer Press: "They didn't like the Gary Sanchez thing with the Home Run Derby, but you can't fix stupid, you know?"
With the Yankees getting ravaged by injuries and Morrison looking for an opportunity, however, the two sides will look to let bygones be bygones.
Among the hitters who are currently on the IL for New York are Bird, Sanchez, outfielders Giancarlo Stanton, Aaron Hicks and Jacoby Ellsbury, shortstops Didi Gregorius and Troy Tulowitzki and third baseman Miguel Andujar.
Righty Luke Voit has held down the fort at first base, and there has been a rotation at designated hitter. The Yanks also recently selected first baseman Mike Ford's contract from Triple-A.
The 8-10 Yanks currently have a righty-centric lineup due to the injuries, so signing Morrison is a low-risk move that could pay big dividends if he manages to recapture some of his 2017 magic.