Darren Fletcher says West Brom team-mate Callum McManaman dived in the 1-0 defeat by Swansea on Boxing Day.
McManaman went down in the box under a challenge from Leon Britton late in the game at The Liberty Stadium, but the referee waved away his protests.
“I think Cal’s made the most of it and that’s why it’s not given. I think everyone can see that, he throws himself,” said Fletcher.
“I think sometimes [if you make] an unnatural movement you don’t get it. Maybe if he tried to stay on his feet, take the hit, and go down he might get a penalty but when you throw yourself like that you’re not going to get them and that’s another one of those frustrating ones.”
McManaman, 24, then confronted Angel Rangel with pair going head to head before escaping with yellow cards.
West Brom boss Tony Pulis defended his player and insisted it should have been a penalty.
“The big disappointment is I’ve just watched the video there and it’s two penalties,” said Pulis after the game.