Injury to apprentice Samantha Clenton seems certain to deny her victory in the Rising Star Series and threatens her bid for the NSW junior premiership.

Clenton came off the unplaced Canny Henry after the winning post at Newcastle on Saturday, hurting her neck and chest.

She remained in John Hunter Hospital on Monday waiting for the results of scans.

Clenton does not expect to ride in the final heat of the Rising Star at Hawkesbury on Tuesday leaving Claire Nutman and Jess Taylor to fight it out.

Nutman sits equal with Clenton on 32 points while Taylor on 26 needs to win and hope her rival doesn't figure in a minor place.

The first-placed rider gets seven points, second five and third three with one point to each of the unplaced jockeys.

Nutman rides the Stephen Farley-trained Regarding Henry, a last-start winner at Cessnock.

"Regarding Henry is a last-start winner. He likes a soft track and gets in with just 52 kilos on his back which will be a big help," Nutman told Racing NSW.

"It's a competitive series and it would be a nice accomplishment if I did win it.

"It would be a highlight to look back on later in my career."

Tuesday's Class Two handicap over 1800 metres is the 25th heat in the series.

The incident at Newcastle could also cost Clenton the NSW premiership with leading metropolitan apprentice Winona Costin on 64, five behind in the statewide title race.