Bates has penned a three-month deal at the Coral Windows Stadium and is scheduled to be in the squad for the encounter with Tranmere after receiving the necessary clearances.
His current deal with the club will keep him in Parkinson's squad up to and including City's home match with Bristol City on 11 January 2014.
The 26 year-old can play in a varied number of positions in defence and midfield, including right back and as a holding midfielder, but he is best known for his performances at centre half.
Bates' arrival at Valley Parade comes just days after City defender Andrew Davies was ruled out for three to four months following knee surgery.
Bates will wear squad number 22 this season for the Bantams.
The Stockton-born defender made his professional debut with Middlesbrough in December 2004 after helping the Teesiders win the F.A Youth Cup the season before.
Bates was actually joined by City midfielder Jason Kennedy in Middlesbrough's successful Youth Cup triumph, while Bates, Davies and Kennedy all made up part of the 'Boro squad that reached the final in the same competition during the 2002/2003 season.
After spending loan spells with Darlington, Ipswich Town and Norwich City earlier in his 'Boro career, Bates would eventually go onto make over a century of appearances during his eight-year spell at the Riverside Stadium.
One of the highlights of his time with Middlesbrough came during the 2005/06 season when he made up part of the squad that reached the UEFA Cup Final (now Europa League) against Sevilla in Eindhoven.
Following his departure from Middlesbrough in 2012, Bates played in the Championship last season with Bristol City.
He has also collected caps at Under 18 and Under 19 level for England.