On 31 January 2017, Brekalo was loaned out to VfB Stuttgart until the end of the season with an option for a further year.

The loan deal was initially automatically extended until June 2018 when Stuttgart secured promotion.

[11] Having represented various Croatian youth teams, Brekalo debuted for the senior squad on 15 November 2018 in a 3–2 Nations League victory against Spain.

Brekalo's father Ante (nicknamed Šargija) is a former footballer, having represented Bosnia and Herzegovina on various youth levels, as he hails from the Bosnian region of Posavina.

In summer 2018, after VfL Wolfsburg decided that captains of all their teams would wear such an armband during the 2018–19 season, Brekalo sparked controversy in German and Croatian media after stating that he would not like to wear a captain's armband with LGBT flag colours.

After "liking" homophobic comments under club's Instagram post of captain Josuha Guilavogui wearing the armband, Brekalo blamed it on a mobile phone malfunction in an interview with Kicker.

He went on to state:[20][21][22] "I have to say that I can't stand completely behind this action, because it contradicts my Christian belief.