Messi on bench for Barca return
Barcelona's Argentinian forward Lionel Messi plays with a ball during an open training session at the Mini Stadium in Barcelona on January 3, 2014
Brazilian forward Neymar misses out for the Catalans due to a stomach bug as Martino has made six changes to the side that beat Elche 4-0 on Saturday with this weekend's top of the table clash with Atletico Madrid in mind.
In the absence of Messi and Neymar, Alexis Sanchez, Pedro Rodrgiuez and Cesc Fabregas continue up front for Wednesday's game.
Messi has been sidelined since he tore his hamstring early on in Barca's 4-1 win away to Real Betis on November 10.
After beginning his treatment for the injury in Barcelona, he travelled to his native Argentina to continue his recovery process during December.
He returned to the Catalan capital to take part in training on January 2, but was left out of Martino's squad for Elche clash to allow him a few more sessions alongside his teammates before returning.
Despite scoring 14 times in 16 appearances this season, Messi's campaign has been beset by fitness problems as he was also ruled out for shorter periods in August and October with muscular injuries.