Sharps returned to the club two weeks ago after spending two years at Shrewsbury, where he secured promotion to League One.
And after turning down a new deal he explained why he chose to come back to the Millers, where he spent foiur years previously.
"I wanted a longer contract at Shrewsbury and they weren't prepared to give it, I've got three young children and I need to look after their well being.
"I spoke to a few other clubs but Rotherham are the most ambitious that I spoke to The whole set-up at Rotherham reminds me of when I came to Shrewsbury..With the new stadium and the manager being very impressive in one-to-one situations, it felt right to go back.
"I'm proud of what we've done this year. We had the second-best defence in League Two and the third best in the whole of the three divisions."
Ian added: "To drop back down a level probably looks strange to some, but the whole set-up at Rotherham reminds me of when I came to Shrewsbury. They look geared to go up at the very least one division."