The 25 year old midfielder is set to join the Millers after a deal was agreed with Czech club Slovan Liberec.
Christ who spent time on loan at Wigan last term has been watching the Millers pre-season games.
Speaking to the Advertiser, boss Matt Taylor said; “It's now with the Home Office,” manager Matt Taylor said after Tuesday’s 1-0 win over Sheffield United at New York. “It's the most complicated situation I've ever been involved in.”
“He's still contracted to another club so that's why it's difficult to talk about it at length. Until he's no longer contracted to another club and is our player, there's not a lot I can say.”
The Millers will pay a fee for Tiehi's services as he still has a year on his contract with Slovan Liberec.