Six men have been arrested in the ambush shooting of former Boston Red Sox slugger David “Big Papi” Ortiz, as he sat in a nightclub late Sunday in his native Dominican Republic, authorities said.

Prosecutors in the Dominican Republic said Wednesday that the suspects set out to kill Mr. Ortiz and collect an $8,000 bounty placed on him.

In a news conference, police showed reporters the handgun used in the attempted hit job and said a total of seven men were part of the murder plot that left Mr. Ortiz with a bullet wound to the back.

Mr. Ortiz, a 43-year-old retired baseball player still beloved in Boston for his role on three World Series-winning teams, was recovering at Massachusetts General Hospital on Wednesday after being flown there late Monday on a plane provided by the team and undergoing surgery. He also had surgery in the Dominican Republic.

His friend, Jhoel López, a television host, also was wounded in the incident, police said.

Police said earlier that a pair of assailants drove up to the Dial Bar and Lounge, a nightclub in the capital, Santo Domingo, on a motorcycle late Sunday where one of them appeared to approach on foot and open fire, sparking a panic in which diners fled their tables, according to police and video of the incident posted by local media.

Some at the club then nabbed and beat one of the suspects before police took him into custody. He was later identified as Eddy Vladimir Féliz García, who was treated at a hospital for his injuries.

Mr. Ortiz started his career in 1997 with the Minnesota Twins, then played for the Red Sox for 14 seasons before retiring in 2016, according to Major League Baseball. The Red Sox held a moment of prayer for Mr. Ortiz prior to their home game Monday night against the Texas Rangers.