Santana spent the first eight years of his Major League Baseball career with the Cleveland Indians. The 31-year-old posted a .249/.365/.445 slash line from 2010 to 2017.
Last season, Santana hit .259 with 23 home runs and 79 RBI. For his career, he has 174 homers and 587 RBI.
A hallmark of Santana's offensive ability is working counts and drawing walks. He led MLB with 113 walks in 2014, and his 15.2 walk percentage since the start of 2010 ranks third in MLB behind Joey Votto of the Cincinnati Reds and Joey Bautista of the Toronto Blue Jays.
Santana has also been a durable player throughout his career, appearing in at least 143 games in each of the past seven seasons and 152 games in each of the last five.
In addition to his offensive prowess, Santana has turned himself into a solid defensive first baseman. He moved to the position full-time in 2014, and his 10 defensive runs saved last season tied for second among MLB first basemen, per FanGraphs.
Even with a glut of solid first basemen available to teams this winter, including Eric Hosmer, Logan Morrison and Mitch Moreland, Santana is a standout in that group because of his ability to hit, get on base and save runs with his glove.
The Phillies will depend on Santana's usual level of production in the middle of their lineup as they look to make a playoff push next season after missing the postseason for six consecutive years.
Philadelphia's decision to sign Santana may raise some eyebrows since Rhys Hoskins currently occupies first base. Hoskins was a revelation last season, hitting 18 home runs in 170 at-bats.
Moving Hoskins to the outfield is a possibility.
Santana can also play third base, although Maikel Franco mans the hot corner for the Phillies. Santana has limited experience in the outfield as well and has caught 330 games in his career, but he hasn't been behind the plate since 2014.