Marcus Smart is ready to make his return.

The Celtics announced Monday the guard has been upgraded to available for the team's Game 4 matchup against the Bucks.

Smart, who was cleared for full contact one day earlier, played 3-on-3 Saturday and was a full participant in practice Sunday. He was in high spirits while speaking to reporters, saying he was hopeful to make his postseason debut this week.

Despite dealing with a "tough" rehab process, Smart will get back on the court ahead of schedule, as he was initially expected to be out four to six weeks when he tore his oblique in mid-April.

"We're taking it day-by-day,” Smart said Thursday. "Unfortunately, there's nothing really you can do. One day it might feel good, one day it might not. So, you've got to take it day-by-day and take it slow.

"Pain level is going down. The breathing is getting better. It's not as sore, so that's even better. Mild contact, in the fact I get bumped, like just walking down the street, two weeks ago that was excruciating pain for me. This week it is better.”

Smart, 25, finished the regular season averaging 8.9 points, 2.9 rebounds and four assists. He shot 42.2 percent from the field and 36.4 percent from 3-point range.

Milwaukee, holding a 2-1 series lead, is slated to visit Boston at 7 p.m. ET Monday.