In the aftermath of left knee surgery, All-Star point guard Kyrie Irving of the Boston Celtics will miss the rest of the regular season and playoffs, the team announced.

Who Will Lead Celtics on Offense? Since Kyrie Irving last played on March 11, Marcus Morris is the team's leading scorer while Terry Rozier leads the team in shot attempts per game (15.2). Marcus Morris 20.8 Jayson Tatum 17.2 Terry Rozier 16.6 Jaylen Brown 14.0 Al Horford 12.8 -- ESPN Stats & Information

Irving will undergo another procedure on Saturday to remove two screws from his patella that were inserted in 2015 to repair a fracture he suffered during that year's NBA Finals. The team said a bacterial infection was discovered at the site of the screws when Irving had his most recent surgery, on March 24, to remove tension wire in the knee and that Saturday's procedure will ensure no infection remains.

The wire had been placed in his knee during the same surgery in which the screws were inserted in 2015.

The Celtics said Irving's patella is completely healed and "remains structurally sound." Irving is expected to recover fully in four to five months, the team said.

Celtics team sources told ESPN's Jackie MacMullan that Irving experienced "immediate relief" once the tension wire was removed, and the team believes that was the source of pain that has hampered him for much of this season.

While the presence of bacteria was unexpected, the team sources said, it is not particularly uncommon when dealing with hardware in surgeries. The bacteria that was detected was not MRSA, a staph infection that is often resistant to antibiotic treatments.

One team official told MacMullan that surgeons reported the cartilage, ligaments and tendons surrounding Irving's kneecap also were strong and intact.

"I actually think Kyrie will come back from this surgery even better than before," said the team source.

Irving reflected on the news in an Instagram post Thursday and wrote, "This season was only a snapshot of what's to come from me."

The loss of Irving is a devastating blow for Boston's hopes of competing for the Eastern Conference championship. The Celtics (53-25) hold the No. 2 seed in the conference. Irving, who last played in a game on March 11, averaged 24.4 points, 5.1 assists and 3.8 rebounds this season, his first in Boston.

Boston acquired Irving in a blockbuster offseason deal with the Cleveland Cavaliers.

The Celtics are expected to sign free agent Jonathan Gibson, according to league sources. The 30-year-old Gibson played for Boston's summer league squads in 2012 and put up big scoring numbers in China earlier this year. The 10-day contract of Xavier Silas, originally signed via Boston's injury hardship exception, expires Friday.

The Celtics are still without guard Marcus Smart, who had right thumb surgery in March. He's hopeful to be able to return sometime early in the playoffs. Smart has been working out at the team's practice facility with protection over his right thumb as he recovers from surgery. The Celtics are hoping to have a firmer grasp on a potential return timeline next week, according to sources.

Celtics president of basketball operations Danny Ainge has stressed that he does not expect Smart to be available in the first round of the playoffs.

After Thursday's news, the Celtics' odds at the Westgate Las Vegas SuperBook dropped from 20-1 to 80-1 to win the NBA title and from 9-2 to 20-1 to win the Eastern Conference.

Ainge said his depleted Celtics team will persevere in the postseason, just as it has all season amid mounting injuries, and not dwell on the "what-ifs" of a difficult year.

"It was so fun in training camp to watch Kyrie and Gordon (Hayward) and Al (Horford) play together," Ainge said. "Our young guys were blossoming, and it was just amazing how quickly things were working.

"Then, as the season went on without Gordon, we got to see how well guys responded, and turned a terrible thing into a positive. Even after Kyrie went down, our guys had the mindset of 'OK, we're going to make a really good run here.' But now we've lost Daniel (Theis), Marcus (Smart)and Kyrie.

"It's part of what we go through. It's not fun for anybody, but our guys won't quit right now, I'll tell you that."

ESPN's Chris Forsberg contributed to this report.