MINNEAPOLIS -- Jorge Polanco underwent arthroscopic debridement surgery on his right ankle on Friday to repair an ankle impingement, the Twins announced on Wednesday. Polanco is expected to resume baseball activities in around six weeks and should be ready for Spring Training.

The procedure was performed by Dr. Richard Ferkel in Los Angeles. According to the Twins, the injury wasn't caused by any specific play or action, and it is characterized as a chronic issue that occurred due to repetitive stress.

Polanco is expected to wear a protective boot for the next few weeks as he works on ankle motion immediately and then on strengthening the area in 1-2 weeks.

Twins manager Rocco Baldelli had hinted towards the end of the season that Polanco had been playing while dinged up, but the club had to rely on its shortstop due to a severe rash of injuries elsewhere in the infield and outfield. Polanco appeared in a team-leading 153 games and finished fifth in the American League with 704 plate appearances. No other Twins player appeared in more than 137 games.

Polanco still finished with career highs across the board after a breakout campaign during which he hit .295/.356/.485 with 22 homers and 40 doubles. He finished third among AL shortstops with 186 hits and became the first Twins shortstop to start for the AL in the All-Star Game since 1979.

Twins lose Hefner, Shelton

Assistant pitching coach Jeremy Hefner has informed the Twins that he will not return after receiving the pitching coach job for the Mets, an industry source confirmed after the news initially broke on Tuesday.

The Twins will progress with a search for the assistant pitching coach position after having just promoted Edgar Varela to fill their vacancy at hitting coach on Monday. The Twins are still far from finalizing their 2020 coaching staff under Baldelli, as bench coach Derek Shelton was named the new Pirates manager on Wednesday.

Shelton and Hefner are the fourth and fifth high-level coaches to depart the Twins' organization this offseason for Major League jobs, joining former hitting coach James Rowson (Marlins bench coach/offensive coordinator), Minor League hitting coordinator Peter Fatse (Red Sox assistant hitting coach) and Minor League catching coordinator Tanner Swanson (Yankees catching coach).