Odoffin joins the Millers for an undisclosed fee from Hamilton Academical.
The Midfielder spent 18 months with the Accies and made 41 appearances for them last season, proving to be one of their best players.
Speaking to the clubs Ifollow service today, the 23 year old said; “It feels great to be here, I’m so happy for everything to now be over the line, it has been going on for a long time and I’m happy to finally get it done."
“I held talks with the gaffer and the coaching staff prior to joining. They showed that they wanted me here and they showed intent, that meant a lot to me."
“I’m buzzing with the move. Not only to get back into the English leagues, but it is closer to home as well. I just can’t wait to get started.
“I can play right-back, centre-back and midfield. I played central defensive midfield for the majority of last season and I enjoyed it. Wherever the gaffer wants to put me I’m going to give 100% and that is main thing.” he added.