Rhys Williams, the Wales' 400 metres hurdles champion, has been provisionally suspended after being charged with an anti-doping violation.
The 30-year-old, the son of rugby union great JJ Williams, becomes the second Welsh athlete to be forced out of the Commonwealth Games over an alleged anti-doping violation after 800m runner Gareth Warburton.
Welsh Athletics said in a statement: "Welsh Athletics can confirm the provisional suspension of Rhys Williams after being charged with committing an anti-doping rule violation under the IAAF Anti-Doping Rules.
"Rhys has the opportunity to respond to the charges against him and to have those charges determined at a full hearing before the national anti-doping panel.
"Welsh Athletics strongly supports clean sport and has established a comprehensive education programme for its athletes.
"Welsh Athletics is obviously concerned that this is the second anti-doping violation by a senior Welsh international athlete and will be conducting its own internal review.
"Welsh Athletics will not be making any further comment."
Only weeks before the Games began, Williams said how much he was looking forward to Glasgow 2014 in an exclusive blog for The Huffington Post UK.