The Vics had to call on debutant Jack Prestwidge as an emergency substitute after second-gamer Sam Elliott was ruled out under concussion rules late on day three.

Elliott was hit in the helmet grill and carried on at Junction Oval on Saturday, but asked for painkillers about an hour later and was retired by umpires to undergo a concussion assessment.

He protested with Cricket Australia's medical staff before failing the test.

Victoria had already lost Sam Harper and Jon Holland because of positive COVID-19 results the previous day and could not call in a replacement for tail-ender Elliott (26 retired hurt) before losing their ninth and ultimately final wicket.

It brought their second innings to a close at 9-283, leaving NSW a target of 233 runs to win.

The Blues were 1-58 at stumps with Daniel Hughes (31 not out) and Jason Sangha (16no) at the crease.

Off-spinner Todd Murphy (1-22) made the only breakthrough for Victoria when he trapped NSW captain Kurtis Patterson (7) lbw, and had another big shout against Sangha turned down.

Sangha rubbed salt in the wound when he whacked the next ball to the boundary.

Prestwidge was hastily presented with his Victoria cap before entering the fray for his maiden first-class appearance in the fourth innings of the match.

He had made a late dash to the ground from the other side of Melbourne, where he had been on club cricket duties.

"It's been crazy at times," Victorian batsman Campbell Kellaway said.

"There's been blokes coming in and blokes going out, but I'm just trying to keep myself on the park.

"Everyone who's stepped up has played a role and everyone's been ready to go and if required they've done a job for the team, which has been awesome.

"I think (Elliott) is feeling alright ... he was smacking them out there so it was a shame he had to come off, but obviously you've got to look out for his best interests."

Victoria had second-gamer Kellaway to thank for pushing their lead beyond 200.

The 20-year-old scored a team-high 81, including 13 boundaries, in an impressive batting display after the Vics' top order crumbled.

Chris Tremain (2-50), Mickey Edwards (2-56), Chris Green (2-27) and Moises Henriques (2-29) all claimed multiple wickets for NSW.

Both sides are fighting for their first Shield win of the season in what is the first game for the last-placed Blues under caretaker coach Greg Shipperd, after Phil Jaques was axed earlier in the week.

Australian Associated Press