The deal includes an opt-out date of July 1, and Morrison, 31, will make $1 million if he's added to the major league roster, sources told ESPN's Jeff Passan.
Morrison hit .239 with 15 home runs and 39 RBIs in 95 games for the Minnesota Twins in 2018 before he was sidelined by a torn labrum. He had surgery in August that was expected to keep him out for eight months, and he used the rehab time to retool his swing to better resemble that of 2017, when he hit 38 home runs for the Tampa Bay Rays.
Earlier this week, the Yankees added first baseman Greg Bird to the injured list with a left plantar fascia tear. It's unclear how long Bird will be out. Manager Aaron Boone guessed Tuesday that the injury might keep Bird out "at least a month."
"Obviously [Morrison's signing is] just some depth right now, and a guy that has a proven big-league track record," Boone said. "Just good for us to get somebody that if we got into a situation, that's capable of doing some damage if he got up here."
In 2017, Morrison had a celebrated feud with Gary Sanchez when he said the Yankees catcher didn't belong in the Home Run Derby. Morrison was left out of the contest despite hitting 24 home runs before the All-Star break.
"Gary shouldn't be there,'' Morrison said at the time. "Gary's a great player, but he shouldn't be in the Home Run Derby.
Sanchez had 14 homers when he was selected for the contest
"I remember when I had 14 home runs,'' Morrison said then. "That was a month and a half ago. It's par for the course. I play for the Rays. I get it."
On Friday, Sanchez indicated, through an interpreter, that the rift is long behind him.
"That's a long time ago. We're way over that stuff," Sanchez said. "Now he's a teammate, and we're going to treat him as a teammate, and we're going to welcome him into this clubhouse. There's no sense of talking about something that happened so long ago."
Also Friday, with Domingo German and CC Sabathia fortifying the Yankees' rotation, sources told Passan there is an increasing sense that left-hander Gio Gonzalez plans to opt out of his minor league deal Saturday. The Yankees would have 48 hours to add Gonzalez to their roster, and if they don't, he will become a free agent.
Gonzalez would have a $3 million base salary in the majors, with incentives of $300,000 for every start.
A two-time All-Star who spent seven seasons with the Washington Nationals, Gonzalez has allowed 10 runs in 15 innings over three starts in Scranton/Wilkes-Barre. His scheduled start for the RailRiders on Friday in Buffalo, New York, was postponed due to rain and rescheduled as part of a doubleheader Saturday.
"We'll see," Boone said. "He's pitched pretty well, and those are the conversations that obviously pick up steam here, obviously, with some urgency in the next couple of days."
ESPN's Coley Harvey and The Associated Press contributed to this report.