The veteran right-hander returned to the mound in September after missing most of the season with a shoulder injury, but he'll opt to retire after suffering a setback in January that would have necessitated surgery. Hellickson had a 10-year career spanning stints with the Rays, Diamondbacks, Phillies, Orioles and Nationals, and he earned AL Rookie of the Year honors in 2011. He had a career 4.13 ERA and 1.25 WHIP with 929 strikeouts and 76-75 record in 232 games.

The 10-year veteran has been limited by injuries to just 130.1 innings over the last two seasons combined. He didn't look good in his 39 frames for the Nationals last season, struggling to a 6.23 ERA and a 10.9 percent walk rate. He hit the injured list in late May due to a shoulder strain and never returned to big-league action. With the issue worsening to the point that his 2020 campaign is already in doubt, it's possible the 32-year-old has already thrown his final major-league pitch.

Hellickson hasn't seen major-league action since going down with shoulder tendinitis in mid-May, but he'll rejoin the Nationals for the stretch run. According to Mark Zuckerman of MASN Sports, Joe Ross will remain in the starting rotation to pitch Monday against the Mets, meaning Hellickson should work out of the bullpen.

After completing a simulated game last week, Hellickson received the green light to make his first appearance at any level of affiliated ball since May 19. The lengthy layoff means that Hellickson will require multiple minor-league starts to build up his pitch count in preparation for a potential return to the Washington rotation in late August or early September. If healthy, the 32-year-old could represent an upgrade over current back-end starters Joe Ross and Erick Fedde.