Hartnell is set to run in his first Caulfield Cup, with the Godolphin team opting to give the veteran his chance to win the $5 million handicap under top weight of 58kg.
The James Cummings-trained Hartnell was paid up for Saturday's Group One Caulfield Cup (2400m) on Wednesday and the nine-year-old gelding will be ridden by Brad Rawiller in the capacity field.
Rawiller won the Caulfield Cup a decade ago on Viewed who was trained by Cummings' s grandfather Bart.
Hartnell is yet to win to win this year but has finished in the top four in nine of his 10 starts during 2019 including his most recent third in the Group One Turnbull Stakes (2000m) at Flemington in which Caulfield Cup favourite Finche was second.
"The thing about Hartnell is Hartnell can run well in any race you put him in," Cummings said.
"We've always sought to tailor his preparation to what he's looking for and after a really good Caulfield Cup trial in the Turnbull Stakes we were enthused to bring him back to Caulfield at a track where he's raced so beautifully in the past."
Hartnell, a four-time Group One winner, has run in three Melbourne Cups including a third placing in 2016.
He won the Group One Epsom Handicap (1600m) at Randwick last spring carrying top weight of 57kg.