Boston Celtics All-Star Kyrie Irving will undergo what the team is referring to as "minimally invasive" surgery on Saturday with hopes of combating soreness in his left knee, the team announced Friday.

The Celtics did not offer a timeline for Irving's return, noting that "further information will be provided following [Saturday's] procedure."

Irving did not travel with the team for the start of a four-game road trip that opened Friday night with a 105-100 win over the Portland Trail Blazers.

He has missed five games because of left knee soreness this month and was forced to sit out the second half of a March 11 loss to the Indiana Pacers when the soreness flared. Irving has noted that soreness initially flared during a March 3 loss in Houston.

With the Celtics firmly entrenched in the No. 2 spot in the East, Irving had said he wanted to take an extended rest in hopes that the knee soreness would dissipate. He traveled with Boston for a two-game road trip last week, but the knee showed little progress. Irving sought a second opinion to get a better idea of how to combat the soreness.

Kyrie Irving will undergo surgery on his injured left knee, with the Celtics describing the procedure as "minimally invasive." Garrett Ellwood/NBAE via Getty Images

Irving's ailing knee is the same one that he injured during the 2015 Finals and required surgery on his kneecap. Celtics president of basketball operations Danny Ainge has previously noted that the team was aware it would have to manage Irving's workload when the Celtics acquired him this past summer and said that Irving may need a follow-up surgery in a future offseason to alleviate the soreness flare-ups.

For his part, Irving said earlier this month that he was hoping to avoid surgery.

Irving, who celebrates his 26th birthday Friday, is averaging 24.4 points, 5.1 assists, and 3.8 rebounds in 60 appearances this season. He is playing 32.2 minutes per game, down nearly three full minutes from last season. Excluding his rookie season, it's the lowest average of Irving's career outside of when he played 31.5 minutes per game while working his way back from the initial surgery during the 2015-16 season.

The Celtics, ravaged by injuries beyond Irving's knee, are 4½ games back of the East-leading Toronto Raptors but six games ahead of the Cleveland Cavaliers.

Stevens said the team will focus on its strengths in light on the injuries, although Brown could return as early as Sunday in Sacramento.

"Do what you do best. That's it,'' he said after Friday's win. "Everybody's got something they do well otherwise they wouldn't be in the NBA. Don't try to be something you're not, don't try to make up for Kyrie's absence, or Smart's absence, or Tyson's absence by trying to do what they do. Just do you and just be good at it, be reliable at it. That's all we're going to ask.''

The Associated Press contributed to this report.