The Royals made official the addition of right-handed relief pitcher Brad Boxberger to help solidify the back end of what was the American League’s worst bullpen last season. A former American League All-Star with Tampa Bay, Boxberger signed a one-year deal with the Royals.

Boxberger received a $2.2 million deal with up to $1 million in incentives, a source told The Star. Boxberger gives the Royals another option in someone who has experience closing games at the big-league level.

The Royals and Boxberger had been closing in on a deal on Wednesday, and the club announced the signing on Thursday afternoon.

As for the incentives, Boxberger can make up to $500,000 (maximum) relative to number of games pitched and another $500,000 (maximum) relative to number of games finished.

Boxberger, a right-hander who was a 2015 All-Star with the Tampa Bay Rays, has posted a 3.42 career ERA and a 20-27 record in 291 appearances (all in relief). He’s logged a 2.54-to-1 career strikeout-to-walk ratio with a 1.28 WHIP and 76 career saves.

Boxberger, 30, has averaged 11.6 strikeouts per nine innings and 4.6 walks per nine in seven big-league seasons.

Last season, Boxberger saved a team-high 32 games and finished 45 games in 60 appearances for the Arizona Diamondbacks. He struck out 71 batters and walked 32 in 53 1/3 innings while opponents batted .221 against him.

The addition of Boxberger gives the Royals bullpen two relievers who’ve had some success closing games. Along with Boxberger, Wily Peralta showed signs of being able to handle a late-inning role with 14 saves last season — 12 after the All-Star break.

Peralta, a right-hander, converted 14 of 14 save opportunities after the Royals traded Kelvin Herrera. Peralta averaged slightly more than a strikeout per inning last season (35 in 34 1/3 innings). While opposing hitters batted a career-low .230 against Peralta, he also walked 23 batters in 34 1/3 innings for a WHIP of 1.485 last season.

Right-hander Kevin McCarthy gave the Royals another consistent option out of the bullpen last season. McCarthy was the only other reliever on the ballclub with a sub 4.00 ERA in 30 appearances or more out of bullpen. (Left-handed reliever Brian Flynn posted a 4.04 ERA.)

Boxberger, a California native, made his major-league debut in 2012, and he has pitched for the San Diego Padres, Tampa Bay Rays and Arizona Diamondbacks.

During his All-Star season of 2015, he saved a career-high 41 games. He was selected to the AL team that season by Royals manager Ned Yost, who was manager of the AL side that year.

The Royals drafted Boxberger out of high school in 2006 in the 20th round, but he went to college at Southern California instead. He then became a first-round selection by the Cincinnati Reds in 2009.

Royals’ pitchers and catchers report to the team’s facility for spring training on Feb. 12, in Surprise, Ariz.