Boston Celtics star Kemba Walker is "doubtful" for Monday's NBA game against the Sacramento Kings due to a neck sprain.

Celtics guard Walker was hospitalised following a scary collision against the Denver Nuggets at the Pepsi Center on Friday.

The three-time All-Star – with his head down – bumped into team-mate Semi Ojeleye during the second quarter of Boston's 96-92 loss.

After the Celtics provided an update on Walker earlier on Sunday, head coach Brad Stevens told reporters: "Obviously they went through a series of things with the Denver doctors, and a series of things when he got back yesterday with our doctors.

"So he is continuing to be monitored in case any of that stuff shows up.

"But he's been good, and he feels good. It's kind of a minor miracle based on what we saw the other day. But the strain is real, and he's got some soreness in his back and neck. That's it."

Walker, who did not practice on Sunday, had been averaging 22.6 points, 4.9 rebounds and 4.8 assists per game heading into the clash against the Nuggets.

"It's always scary. And that's the reason he's doubtful [for Monday], to be honest," Stevens added. "I think he could probably play with the strain part, but we want to make sure [that] with the way he hit, and certainly because of the sensitivity to head injuries."