WESTERN Bulldogs coach Rodney Eade believes Scott Welsh's interchange infringement cost his teammates the chance to challenge St Kilda after a third-quarter rally had brought them within 18 points.

Eade said Welsh's decision to start the fourth quarter on the field after not reading the match-up board had weakened the Dogs' pressure on the unbeaten Saints.

Two weeks after chasing down Collingwood from a 34-point three-quarter time deficit only to lose by a point, the Bulldogs had kicked three of the last four goals before the final change of Saturday night's clash.

But when the sides broke from their huddles and returned to play, the Dogs had 19 players on the field. An emergency umpire spotted the error and alerted the field umpires.

As Welsh left the ground, the Saints were handed a free kick, 50m penalty and resultant goal to Nick Riewoldt.

"We hadn't played well in the first half, but the third quarter was good and we had a bit of momentum," Eade said after the game.

"It was always going to be tough with two quality players off and being short, but having said that we were still confident enough at three-quarter time.

"It certainly wouldn't have changed the result. They played extremely well and they thoroughly deserved winning by as much as they did.

"It probably took the wind out of our sails a little bit. If that hadn't happened, we might have got a little bit closer but I don't think it had an impact on the result."

Eade said he spoke to Welsh after the game but would not punish him for the mix-up.

"I don't think he realised," he said.

"[After the game], I asked him if he'd read the match-up board and he said he didn't.

"I said, 'At 30 years of age, you might have learned something'."

Eade said the Dogs failed to take their chances throughout the night and again made basic errors against what he considered the benchmark side.

"Their pressure was good but I think there was a lot of inferred pressure. I thought our guys didn't handle the situation at all," he said.

"In the first half there were a lot of unforced errors, a lot of fumbles, making incorrect decisions.

"You've got to give full credit to the opposition. We were another one of the teams to fall into their pressure, so obviously we've got some work to do."

Eade confirmed the hamstring injuries to forwards Shaun Higgins and Robert Murphy and said Higgins would miss at least two weeks.

Murphy is likely to be sidelined for one.

"It was sort of like a cramp and they were confident he would be able to get back on, but every time he started to run it started to cramp," Eade said of Murphy.

"He'll certainly miss next week, so we're hopeful there's no damage there and it will only be the one."

Murphy had also come off during the warm-up, but Eade said it was for patella tendon soreness and had nothing to do with his new injury.

He added that Welsh was fine after having his ankle re-strapped in the first half and that captain Brad Johnson was not sore but "maybe just played poorly".