Fit-again Messi in line for Atletico recall
Both sides are locked on 49 points having dropped just five points each in 18 league games this season.
Messi made a spectacular return from a hamstring injury on Wednesday as he scored twice as a second-half substitute in the Catalans' 4-0 thrashing of Getafe in the Copa del Rey.
The Argentine's form leaves coach Gerardo Martino with a difficult decision as to who to start up front at the Vicente Calderon.
Brazilian forward Neymar is also available after missing the Getafe game with a bout of gastroenteritis, but the triumvirate of Alexis Sanchez, Pedro Rodriguez and Cesc Fabregas have deputised ably in Messi and Neymar's absence in recent weeks.
Midfielder Xavi Hernandez hailed Messi's return as great news for the club heading into such a busy period on three fronts and believes the competition for places can only be a good thing.
"He doesn't surprise you anymore, but to see him in that form is impressive. He has returned hungry. The important thing is that he has returned in good shape and motivated," he told the Barcelona website.
"We are strong and now that we have both him and Victor (Valdes) back there is a lot of competition and the team is looking pretty good.
"The game against Atletico is vital for the development of the league. It is not definitive but if we were to win it would be a strong signal of intent."
Many believe Saturday will be the acid test of whether Atletico can realistically challenge Barca for the title.
However, midfielder Koke was keen to play down the importance of the clash with a further 19 league games still remaining after the weekend.
"It will be an important game because it is between the top two teams in the league. However, it is only one match and the whole second-half of the season is left, although we realise it is the most important game we have played until now.
"What matters is how you finish the season. It doesn't mean anything if you win this game but end up not achieving your objectives at the end of the season."
Messi's return provides another problem for Diego Simeone's men to contend with, but Koke believes the form of Pedro, Sanchez and Fabregas means that Atletico's watertight defence will have to be at their best no matter who starts.
"If he plays we will need to be careful because he is one of the best players in the world, but Barcelona have a lot of great players and we need to be alert to all of them."
Atletico are hopeful that Uruguayan defender Diego Godin will be fit to play after missing Tuesday's 1-1 draw away to Valencia in the Cup due to a thigh strain.
Should Godin make it, the only big decision for Simeone will be whether to start the out of form David Villa against his old side or go with the free-scoring Raul Garcia alongside top scorer Diego Costa in attack.
No matter the outcome on Saturday, Real Madrid will be able to make ground on at least one of their title rivals when they travel to Espanyol on Sunday.
Los Blancos lie five points off the top of the table and will be confident of closing the gap having not lost in any of their last 11 meetings with the Catalans.
Fixtures (all times GMT)
Granada v Valladolid (2000)
Athletic Bilbao v Almeria (1500), Celta Vigo v Valencia (1700), Atletico Madrid v Barcelona (1900), Elche v Sevilla (2100)
Getafe v Rayo Vallecano (1100), Real Betis v Osasuna (1600), Espanyol v Real Madrid (1800), Levante v Malaga (2000)
Villarreal v Real Sociedad (2100)
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