Speaking after his side's 2-0 win courtesy of goals from Luka Milivojevic and Bakary Sako, De Boer criticised the Baggies' approach and seemed to be focusing his comments on right-back Ally Nyom.
"If you want to sell the product of the Premier League and the beauty of the game, the beauty is not those kind of challenges," exclaimed the former Inter boss.
"Of course, when it's a fair challenge, it's no problem, but for example they were really looking for Wilfried Zaha, so we cannot accept that."
"He is one of the most exciting players in the Premier League and I don't want to think about him being out for a couple of weeks or months."
"The first challenge on him should have been a yellow card and then the player knows that he cannot do another one, but instead you give him the permit to do another challenge."
Nevertheless, De Boer praised his player for keeping his cool and not reacting to the rough treatment dished out.
"I think I have to give Wilf a good compliment because he stayed calm and spoke with his feet and he made a big step in that, so compliments to Wilf," he said.
"There were some where they really went for the ball. I had a feeling that they were going more for the legs than the ball at that moment. You know it's hard, but still it's pre-season and every manager wants his players fit to start the league."
"Everybody has their own opinion and I think a lot of times it was fair but there were some challenges that I think there was some doubt about," he concluded.