Barca go into this weekend's derby against Espanyol with their title aspirations given a major boost after victories over Real Madrid and Celta Vigo in the past six days.
Great rivals Real also suffered defeat to Sevilla to leave them two points behind Martino's men who trail league leaders Atletico Madrid by just a single point.
But those positive results have been largely overshadowed by the news that Valdes, who is leaving the Nou Camp in the summer, has played his last game for the club after tearing his anterior cruciate ligament.
It is the latest in a series of injury blows for the champions with Ibrahim Afellay, Lionel Messi, Neymar, Jordi Alba and Carles Puyol having all missed chunks of the season so far.
"It's a very hard blow, but this team has lived blow to blow for a long time and we will move forward," Martino told a press conference.
"This point in the season I thought that everything that was going to happen to us had already happened."
Jose Manuel Pinto will replace Valdes against Espanyol, although at 38 it remains to be seen whether he is a contender for the starting job next season.
Espanyol forward Sergio Garcia has offered his support to Valdes as he prepares to go up against the club where he began his career.
"(Valdes) is a companion and a friend and I can only wish he recovers soon," he told a press conference.
Espanyol's season looks to be petering out as they sit nine points off a Europa League place with just eight games of the season remaining.
But they have lost just one of their last five games, to league leaders Atletico, and Garcia wants his team-mates to apply pressure to their city rivals.
"Barcelona will be focused 100 per cent," he told a press conference.
"Do not let them breathe or they can play easily.
"We are having a good season, imagine what it would be like to beat them at our own ground. It would be fantastic.
"We are in good form. We hope to continue that streak with a victory and that would be very important.
"Hopefully it will be a nice derby and that we can get the three points."