The Frenchman was diagnosed with a tumour in his liver in March 2011, yet featured for the full 90 minutes in Barca's 3-1 Champions League final win over Manchester United hardly two months later.
Abidal was dealt another blow in March 2012, though, when it was announced that he needed to undergo a liver transplant, and the defender has since been working on his recovery.
"Everything Eric has done and everything he has fought for is admirable. No-one truly knows how hard he has worked to be able to train with the team again," Messi told reporters.
"It was very difficult when we found out [he had cancer] but his strength has united the whole team. How much he can contribute to the team is irrelevant, the important thing is that he is here with us.
"The illnesses to Tito [Vilanova] and Abidal have had a huge effect on us but we are a strong team and we will overcome this."
Abidal was recently given the green light by Barca's medical staff in late February and could make his comeback in the upcoming weeks.