The 3-0 defeat at Middlesbrough was not only a disappointing scoreline, but the manner in which the Whites lost the game will frustrate manager Rosler.
Giuseppe Bellusci not only failed to clear Christian Stuani's cross for David Nugent's opening goal, but then headed in to his own net to make it 2-0 to Boro. His defensive partner Sol Bamba then slipped to hand Diego Fabbrini a clear run at goal for the third, with a number of errors costing Leeds the game at the Riverside Stadium.
Liam Cooper has also had his error-strewn moments this season, which prompted Rosler to hand Bellusci a chance against Middlesbrough - a decision which backfired as the Italian endured a nightmare on Teesside.
Now, having landed Will Buckley on loan from Sunderland, Rosler may well have to return to the transfer market in order to solve his defensive problems at Elland Road.
Rosler could now be prompted to look to the Premier League for a new signing to help solidify his defence, with names such as Mike Williamson of Newcastle or Watford's Tommie Hoban could be available for loan deals, with either player able to aid Leeds' defensive woes.
The signing of Buckley had been seen as a signal that Leeds had ended their transfer activity, but the performance of Bellusci against Middlesbrough should be conerning enough that Leeds find the funds to make one more loan signing ahead of the January transfer window.
Right now, centre backs appears to be the main position of concern for Leeds, and whilst the Whites won't want too many loan players in their side, strengthening the defence would help Rosler push the club forward - and Massimo Cellino must back his manager with a new defender if he wants to see Leeds make progress this season, or risk more afternoons like the nightmare at Middlesbrough this season.