Tony Pulis believes managers have never been under as much pressure as they are now.

The issue of stress for managers in the modern game has come under the spotlight again this week with Blackburn boss Sam Allardyce getting ready to undergo heart surgery tomorrow.

Tests have revealed that Allardyce, 55 - who has complained of chest pains in recent weeks - requires an angioplasty to widen a narrowed coronary artery.

Stoke travel to Blackburn on Saturday in the Barclays Premier League, where Rovers assistant manager Neil McDonald will take charge of first-team affairs for the third consecutive match.

Allardyce is expected to return to work on Monday, but Pulis has warned that the demands placed upon managers at the highest level are greater now than ever before.

"There is more pressure now than there has ever been on managers in respect of getting results," Pulis told Press Association Sport.

"The media now has become an absolute monster.

"Whether it's the internet, radio, television, there are always areas of debate, but you have to accept it.

"We know where we are and what job we are doing and we know that all the experts are sat in the stand." Pulis, who ran the London Marathon earlier this year, said he was always conscious of keeping himself fit and healthy.

"You never like to see anybody in Sam's state, having to go in and having an operation," he said.

"I work hard fitness-wise, try and keep myself as fit as I possibly can in the time that I get."

Blackburn go into the game off the back of a 3-0 defeat at Fulham last night, but they outplayed the hosts for most of the first half.

Prior to that the team ended a 10-match losing streak of away league fixtures with a 2-0 win at Bolton in McDonald's first match at the helm, and Pulis expects to see Rovers put in another committed performance on Saturday.

"I think they will be doubly determined to do well for Sam," Pulis said.

"It will be a tough game. They were very, very unfortunate last night not to be in front and Fulham scored with their first real effort on goal.

"They will have felt very hard done by. The second half was different and Fulham came out and played with a little bit more purpose, but Blackburn will be disappointed that they didn't get anything out of the game."

Stoke returned to winning ways last weekend with a hard-fought 1-0 victory over bottom-placed Portsmouth.

Several sections of the crowd at the Britannia Stadium appeared disgruntled with their team's first-half display, but Pulis was keen to put things into perspective.

"It was a great three points," he said.

"We didn't play well in the first half, but second half, I thought looking back at the game we were the better team and created all the real opportunities.

"There are no gimmes in the Premier League.

"We have to remember that Pompey have been a Premier League side for about five years and won the FA Cup last year.

"But they turn up at the Britannia now and everyone expects us to beat them."