Sharps, 32, has played 27 times in all competitions this season for the Millers, but has found himself out of the side in recent weeks due to the form of Kari Arnason and Johnny Mullins.
"Burton have asked the question on a couple of occasions and added to the fact that Craig Morgan will return to action shortly, it made sense for me to sanction the loan move," said Millers boss Steve Evans.
Sharps, who began his career at Tranmere where he made almost 200 appearances during an eight-year period, joined Rotherham for his first permanent spell on a free transfer in August 2006.
He made a similar number of appearances in his first stint for the Millers before moving on to Shrewsbury for two seasons and returned to Rotherham last summer.
