Cuellar believes that the Black Cats, who narrowly escaped relegation from the Premier League last season, will be in better shape come the business end of the 2013-14 campaign.
Carlos Cuellar: "The way we'll approach this pre-season, I think it will make us a lot stronger physically.
"In the last few games of last season, you could see the players pick up little injuries or cramp because we were working so hard to win every match.
"Sometimes, you give more than 100%, and we didn't have that extra fitness we needed. I don't think we're going to have that problem next year."
Saturday August 17 15:00Premier League Sunderland v Fulham Saturday August 24 15:00Premier League Southampton v Sunderland Saturday August 31 15:00Premier League Crystal Palace v Sunderland Saturday September 14 15:00Premier League Sunderland v Arsenal Saturday September 21 15:00Premier League West Brom v Sunderland Saturday September 28 15:00Premier League Sunderland v Liverpool Saturday October 5 15:00Premier League Sunderland v Man Utd Saturday October 19 15:00Premier League Swansea City v Sunderland Saturday October 26 15:00Premier League Sunderland v Newcastle United