Putnam, 31, was a regular in the White Sox’ bullpen from 2014-17 before going down with an arm injury that ultimately led to Tommy John surgery. Prior to that procedure, though, Putnam turned in 139 1/3 innings with a 2.71 ERA, 9.6 K/9, 3.6 BB/9 and a 47.6 percent ground-ball rate. Putnam never lit up the radar gun, sitting at 90.4 mph with his fastball over that four-year stretch on the South Side, but he nonetheless posted a gaudy 16.1 percent swinging-strike rate in that time as well. Beyond that, Putnam excelled in terms of limiting hard contact, as evidenced by a 27.2 percent opponents’ hard-hit rate that ranked well below the league average.
Putnam joins the Red Sox organization with four-plus years of service time and will surpass the five-year mark if he logs any meaningful big league time in 2019. That means that if he’s able to return to the Majors and find success, the Red Sox will be able to control him through the 2020 season via the arbitration process.