[4] In September 2012, Porto bought back 25% of Ba's economic rights for €750,000 from investor "Pearl Design Holding Limited", with his value being estimated at €3 million at that time.

[5] He made his first league appearance for the Dragons on 2 November of that year, coming on as a substitute for injured Maicon in the first half of an eventual 5–0 home victory over C.S.

[6] Ba was sent off for two bookable offences in the final of the Taça da Liga against S.C. Braga on 13 April 2013, the second of which also resulted in a penalty and the game's only goal, scored by Alan in the last minute of the first half.

[12] After a spell at TSV 1860 Munich marred by injury problems, even though he was first choice when available,[13][14][15] he returned to Rayo on 30 August 2017 after agreeing to a four-year contract.

[16] Ba returned to the Spanish second tier on 11 March 2020, signing for Deportivo de La Coruña on a short loan due to Michele Somma's serious injury.