McDermott lost his job as Reading boss on Monday after three-and-a-half years in charge of the Royals, who were beaten 2-1 by relegation rivals Aston Villa on Saturday - their fourth consecutive league defeat - and sixteenth defeat of this season.
The defeat leaves Reading four points from safety in the Premier League and Sky Sports pundit Hinchcliffe believes the club's owners have acted in a bid to revive their team's fortunes before their plight becomes worse.
"I think it's very, very unfortunate," the former England defender told Sky Sports News. "He knows the club inside out and he did a terrific job at the back-end of last season to win the title and get up into the Premier League.
"But again it shows the pressures once you get to the Premier League - it's very, very tough to try and stay in the league.
"There are a lot of clubs having similar problems to Reading so I'm a little bit surprised because they are not exactly adrift at the bottom of the table - they are second bottom and only four points adrift of safety so there's the possibility of staying in the Premier League.
"With nine games to go, maybe the owners have looked at that and thought 'we need to do something now to try and change our fortunes'. But I do feel really sorry for him because I think he's done a great job."
McDermott won 45 per cent of his matches in charge of Reading after joining the club in December 2009.
He led them to ninth in the Championship that season and reached the play-offs in 2010/11, before securing promotion to the Premier League the following season.
But this campaign the Royals have won just five league games and are only off the bottom of the table because they have scored more goals than QPR.
McDermott is the fourth Premier League manager to lose his job this season after Roberto Di Matteo, Mark Hughes and Nigel Adkins, who was sacked by Southampton in January after guiding his team to the top-flight.
"The Premier League is just incredibly tough - it's a step up in level," said Hinchcliffe.
"The competition from the sides that you play week in, week out means it's very hard to continue the great form you might have in the Championship and take it into the Premier League.
"Unless you bring experienced players in it can be hard for a manager. No matter how good he is and no matter how well he knows the club that he is managing, it is very tough because of the competition in the Premier League."
Former Swindon Town boss Paolo Di Canio is the new odds-on favourite with the bookmakers' to succeed McDermott him after he was seen in the crowd at the Madejski on Saturday.