The Black Cats were beaten 4-2 by Leicester City in their Premier League opener on Saturday in a horror start for Dick Advocaat.
Ahead of this Saturday's home clash with Norwich City, O'Shea spoke of Sunderland's need to improve on last season's relegation battle which may require the help of some new signings, especially given winger Adam Johnson has just been ruled out for eight weeks with a shoulder injury.
"To improve on last season, that has to be your target - to make sure we are not going into the last couple of games keeping away from the bottom of the table," he told BBC Radio Newcastle.
"There's still obviously a couple of weeks to go in the transfer window, so in a couple of weeks we will know the full depth of our squad.
"We have lost Adam the other day for a good few weeks now as well - you are going to get things like that and if we do get a few additions in, you would be hoping that's the competition that the manager spoke about for increasing the depth of the squad, but also the quality of the squad.
"It's improving on last season, it's always the case. You are hoping to improve on last season, without a doubt."