The United defender is banned for one match after he was sent off in his side's 0-0 Barclays Premier League draw with Tottenham last weekend - a decision which infuriated Ferguson.
Seeing double: Fergie joked he could play Rafael (left) and pretend it's Fabio (right)
But when asked how he would fill the void for United's home clash with Birmingham on Saturday, the Scot was in jovial mood.
'I might put Rafael in there,' Ferguson said. 'They wouldn't know [the difference]. Their DNA is probably the same.'
Rafael escaped with an £8,000 fine and a warning about his future conduct following an FA disciplinary hearing into his reaction on Friday.
The verdict will be welcomed by Ferguson, who before the hearing outlined why he thought referee Mike Dean was wrong to apply the second booking.
Seeing red: Rafael (left) was dismissed in the second half of United's draw with Spurs
'You hope for common sense,' the United manager said. 'You hope that prevails.
'It was a bad decision to send him off. In a big game it can have an impact, especially with 20 minutes left.'
Fabio, Wes Brown and John O'Shea are all in contention to fill the vacancy left by Rafael, with Ferguson also expected to make a couple of extra changes as his side look to retain top spot.
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'Having to replace Rafael has given us something to consider, plus one or two other changes,' Ferguson said.
'Fabio could replace him. O'Shea and Brown also played for the reserves, so they are a consideration.'
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Explore more:People: Alex Ferguson, Wes Brown, Mike Dean, John O'Shea Places: Birmingham