Messi scored twice in Barca's season-opening 7-0 thrashing of Levante but was substituted at half-time during Wednesday night's Supercopa draw with Atletico Madrid as a precaution after complaining of pain in the back of his left thigh.
Barca today confirmed Messi, who missed the end of last season with an ongoing injury to his right hamstring, had suffered bruising and was a doubt for the trip to Malaga.
If Gerardo Martino is not able to call on the four-time reigning world player of the year for the trip to La Rosaleda, it would be a significant boost for Malaga as the Andalusian side attempt to bounce back from their 1-0 defeat to Valencia.
However, Malaga defender Vitorino Antunes knows Barca have plenty more match-winners in their squad beyond the Argentinian, saying: "Messi is such a strong player, and if he's not in Sunday's line-up then it's better for us.
"Barcelona have other quality players though, and the team doesn't just rely on Messi."
The champions, unsurprisingly, lead the standings after the opening round of fixtures following their mauling of Levante.
The next two teams in the table, Rayo Vallecano and Atletico Madrid, meet at the Vicente Calderon on Sunday in a capital city derby.
Atletico have enjoyed a good start to the campaign, beating Sevilla 3-1 away last weekend before drawing 1-1 with Barca in the first leg of the Supercopa, and coach Diego Simeone is hoping to continue along the same path.
He said following the Supercopa match: "What we have seen tonight makes us think how we need to continue to work along this line."
Also on Sunday, Levante and Sevilla will be looking to get their campaigns up and running following their chastening defeats on the opening weekend while Real Betis play host to Celta Vigo.
On Monday night, Real Madrid travel to Granada hoping to avoid a repeat of last year's shock 1-0 defeat at Estadio Nuevo Los Carmenes.
Madrid needed a late winner from new signing Isco to beat 2-1 Betis at home last Sunday and Granada are hoping to make Carlo Ancelotti's men sweat once again.
Granada defender Diego Mainz said: "We've shown that we can beat them and we're going to try and repeat it. We're going to fight with everything from the first minute against them and if we can get the win then so much the better."
The second round of La Liga matches begins on Friday night with Getafe taking on Almeria with both teams looking for their first points while Athletic Bilbao play host to Osasuna.
On Saturday, Segunda Division champions Elche host a Real Sociedad side with confidence sky-high following their 2-0 Champions League play-off first leg win at Lyon in midweek, while Espanyol host Valencia and Real Valladolid go to Villarreal.