Becchio, who has been on trial at the Millers for the last two weeks, has passed a medical and agreed terms on a second spell in South Yorkshire.
The Millers are waiting for international clearance for the Argentinean, but he should be signed in time to be involved in Saturday's game at Cardiff.
His arrival will provide a timely boost given the Millers were beaten on Saturday in a game they dominated for over 70 minutes against QPR.
Only some lacklustre finishing stopped Rotherham opening the scoring in the first half and they went on to lose 3-0.
"I'd
like to think there will be new faces in for next week," boss Neil Redfearn said.
"Becchio has passed his medical and terms have been agreed so it's just a
question of getting clearance for him. That's a big plus for us. It's extra
competition up top."
Redfearn hopes that Becchio's impending arrival will be complemented by further incomings.
"We've just got to look at our attacking options
- what's out there and what's available - whether it's going to be an attacking
midfield player or whether it's going to be one who plays up front alongside
another striker," he said.
"We'll just have to look at the quality that's
out there. It has to fit with what we've got."
