Skipper Craig Morgan says Rotherham United have to open the cheque book if they are to achieve their Championship aim next season.
The Millers are looking for midtable security and a possible tilt at the top 10 in 2016 after sealing safety in this campaign despite a points deduction imposed by the Football League.
Morgan said: “If you want to sustain yourself in the Championship and then kick on, you have to invest and bring in quality players.
“That’s up to The Gaffer (Steve Evans) and chairman (Tony Stewart).”
Stewart is the man who saved the club from administration and bankrolled their quickfire rise from League One.
“No-one can ever question the chairman for the money he has put into the club,” Morgan added.
“Every fan will be grateful forever for what he has done. Hopefully he can dig a bit deeper because if you stand still you can find yourself sliding down the leagues.”
Evans and Stewart met last week to discuss their recruitment plans over the summer.
Morgan is coming to the end of his contract at AESSEAL New York Stadium, but the club have offered him an improved deal and hope it will persuade him to turn his back on interest from second-tier rivals Bolton Wanderers.
The 29-year-old centre-half said the Millers learned the hard way in their first season in the Championship for nearly a decade.
They finished five points clear of the drop zone even though the league took three points away from them for fielding an ineligible loan player, central defender Farrend Rawson, in the Easter-Monday win over Brighton.
“We definitely have to manage games better when we are ahead,” Morgan said.
“It’s difficult when the opposition are bringing top players off the bench, but we have been in leads in games where we should have kept on to the points we had.”
Meanwhile, ex-Millers favourite Paul Hurst hit out at the referee after suffering play-off-final heartbreak at Wembley.
The former full-back is now boss at non-league Grimsby and saw his side miss out on a chance to re-enter the Football League when they lost a penalty shootout against Bristol Rovers.
Hurst felt man in the middle Ross Joyce could have sent off two Rovers players in the first half of the 1-1 draw and complained: “Before the game, I said I hoped we wouldn’t be talking about the referee afterwards - the referee himself said that. It’s a tough job - I make no qualms about that - but it just felt like we didn’t get the rub of the green.
“I felt he wanted to keep 11 versus 11 on the pitch. But if a sending-off is a sending-off then you have to be brave and make that decision.”