Newcastle United have made a terrible start to the season, and they are still looking for their first league win of the new campaign.
Sinclair has some sympathy for McClaren, though, and he feels that any manager of Newcastle will struggle to recruit the players he wants.
"It's a difficult job at Newcastle, it's a huge club," Sinclair said. "How can Steve McClaren recruit players to the North East at the moment? The teams [Sunderland and Newcastle] are both struggling. I think there's potentially a wage-cap there, and there is a lot of foreign players in the league that like to be close to London."
Sinclair's comments back up a column which Gary Neville wrote in the Telegraph last week, which stated that the sides in the North of the country were in danger of being left behind.
With so much wealth going to London, Sinclair and Neville clearly feel that northern teams have a battle to stop teams from the capital dominating English football in the foreseeable future.
Newcastle will feel that their current squad should be doing better than it currently is, though, after they invested heavily in the previous transfer window.
The Magpies made a number of changes to their first-team squad over the summer, but their new recruits have failed to start well and the side is struggling, as a result.