Hart confirmed he had agreed to the deal in a text message to The Associated Press. The deal is still pending a physical after Hart missed all of last season following surgery on his right knee.
CBSSports.com first reported Hart's agreement.
"Knees good as well as the rest of me. Been working hard and glad to be able to get out there with this exciting club," Hart said in a text message.
If Hart can stay healthy, getting the two-time All-Star for one season on a relatively inexpensive deal could be a significant coup for the Mariners, who have made adding offense a top priority this offseason. It started with the stunning deal for Cano that was agreed to last week and was said to be worth $240 million over 10-years agreement. It continued by adding a needed right-handed bat in Hart that can provide protection in the lineup.
Hart did not play in 2013 because of a right knee surgery in January 2013 after a meniscus tear and joint damage was discovered. It was his second knee operation in a year after having damaged cartilage repaired before the start of the 2012 season.
His last season was one of the best in his career. In 2012, Hart hit .270 with 30 homers and 83 RBIs with Milwaukee. Hart also had 35 doubles in 2012 and posted an on-base plus slugging percentage of above .800 in each season between 2010-12.
For his career, Hart has hit 154 homers and is hitting .276 in 945 games. Hart has spent his entire career with the Brewers. If he's healthy, Hart has the ability to play both outfield and first base and outfield depth is one of Seattle's biggest concerns going into next season. Hart also could be a solution at designated hitter with Seattle unsure if they'll be able to re-sign free agent Kendrys Morales, who was the Mariners top power hitter last season.
Meanwhile, Greg Johns with MLB.com is reporting the Mariners have traded relief pitcher Carter Capps to the Miami Marlins for first baseman Logan Morrison.
Morrison played outfield for his first three seasons with Miami but transitioned to first base last season.
Like Hart, Morrison also is coming off an injury-plagued season that limited him to 85 games where he hit .242 with six home runs and 36 RBIs.