The Argentine, who joined on a season-long loan from Inter Milan, has been waiting for his debut due to the international break, but he insists that he is ready to impress Gus Poyet against Tottenham Hotspur on Saturday afternoon.
"I'm going to be training this week with the side and getting to know them, and if the manager decides, then yes, I'm ready," Alvarez told the Sunderland Echo. "I'm very keen to get underway. It's a new challenge for me. I'm very happy and very hopeful.
"The Premier League really is the best league in the world, so the idea of coming over here was one I really liked.
"Now I've got the opportunity to do it, I look forward to working hard and doing things in the right way."
Sunderland are believed to have the option to sign Alvarez permanently next summer.