Ba joined the Blues from Premier League rivals Newcastle in January 2013 on a three-and-a-half year deal for an undisclosed fee.
The Senegalese international defender has signed an extension which will tie him to the club until 2016.
Halilhodzic, who was born in what is now Bosnia-Hercegovina, has also coached club sides in Croatia, France, Ivory Coast, Morocco and Saudi Arabia.
Germany is the new World Champion
THIRD PLACE
12th July 2014
Brazil vs Netherlands 0:3
Fathi, who has 101 caps for Egypt, was also the subject of a bid by Nottingham Forest in January 2014.
SEMI-FINALS
9th July 2014
Netherlands vs Argentina 2:4
Argentina reached the final - win on penalty shoot-out
SEMI-FINALS
8th July 2014
Brazil vs Germany 1:7
The 52-year-old, who became the first Nigerian to lead the side into the second round at a World Cup, is attracting the interest of other countries.
The Elephants are looking for a new manager after deciding not to renew the contract of French coach Sabri Lamouchi, who failed to guide the side past the group stages at the World Cup in Brazil.
DAY 10
Match 33
Equatorial Guinea vs Algeria 1:3
FACTS
Goal Equatorial Guinea
Emilio Nsue (50')
Assist Equatorial Guinea
Álex Balboa (50')
Goals Algeria
Z. Belaïd (19')
F. Chaïbi (25')
I. Maza (32')
Assists Algeria
A. Hadj Moussa (19', 32')
I. Maza (25')
Algeria
Equatorial Guinea