Richardson has fired rounds of 68-69-70 to be at 9-under-par and in outright second position with Mills carding rounds of 67-69-68 to be at 12-under-par and the only player in the field recording three rounds in the 60's.
Mills has lead this tournament from his opening round 67 and is set to claim the title wire-to-wire. He is coming off a US Amateur Public Links title last week in Bandon and this season has amassed numerous top-20 finishes in main US Amateur events, including the Monroe Invitational and at the NCAA D1 South Central Regional.
With a three stroke buffer moving into the final day Mills will need to have his "A" game as Richardson is currently firing on all cylinders in the US.
"I'm excited about getting out there tomorrow," says Richardson, who's world amateur ranking of 181st is sure to improve following his efforts this week.
"My game was a little sloppy today, but I managed to get out on the range after and sort things out afterwards. Corbin [Mills] is playing well, but I'm just going to go out there to focus on my own game and hopefully things will fall my way."
Richardson is due for a main amateur title.
The move from his native Tasmania to his present base in Melbourne has given the 24-year-old access to coaching and training sources which Richardson has taken to with gusto.
With more than three years of main international experience under his belt, Richardson can be considered one of the more seasoned competitors on the world amateur stage.
"I have a lot of confidence out there at the moment," says Richardson.
With experience comes confidence and that's a necessary ingredient for any player when trying to close out a championship on the final day.
"I'm just going to try and enjoy the day tomorrow," he says.
"If a result falls my way that's a bonus, but my game is there so hopefully a few putts will drop and I'll post a low number."
Todd Sinnott is the next best of the Australian contingent behind Richardson with the Victorian carding rounds of 69-71-72 to be at 4-under-par and in a tie for 13th position, one stroke ahead of Cameron Smith with the 2011 Australian Amateur Stroke champion at 3-under-par with rounds of 69-72-72 to be in a tie for 19th position.
New Zealander, Ben Campbell, is in the mix at 1-under-par after rounds of 76-66-73, with Campbell's second round 66 the tournament low round to date.
"I've not been fully fit over the last few weeks, but got a good round away here at the Players," said Campbell after suffering a foot injury a few week's back.
"The body seems to be on the mend so I'm looking forward to being back to full health as the game is starting to feel really good. The 66 gave me a lot of confidence and hopefully I can take that form into next week."
Fifty players, which included seven Australians, made the cut which was 4-over par.
Ryan McCarthy is in a tie for 23rd position following rounds of 71-72-71 to be at 2-under-par, Matt Stieger is at 2-over-par after rounds of 70-75-73 to be in a tie for 39th position, with Nathan Holman a stroke back at 3-over-par.
Brett Drewitt was the last of the Australians to make the cut at 4-over-par after rounds of 74-71-75.
Tim Hart will have Sunday off after firing rounds of 74-77-76 to finish at 11-over-par, as will Tarquim MacManus, with the 2011 Master of the Amateurs champion carding rounds of 82-69-77 to be at 12-over-par.
The winner of the 54-hole tournament earning an exemption into the 2012 RBC Heritage.
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