Marland Yarde has been dropped by Harlequins for their Champions Cup trip to Wasps due to an "internal disciplinary matter".
The England international's place on the right wing at the Ricoh Arena will be taken by Charlie Walker, the club confirmed ahead of kick off.
"Charlie Walker starts on the right wing after Marland Yarde was withdrawn from the squad following an internal disciplinary matter," a statement read. "The club will make no further comment on this."
Yarde's withdrawal from the Quins starting XV is one of three changes forced upon director of rugby John Kingston, after Will Collier and George Merrick both failed fitness tests.
Collier's place in the front row has been taken by Phil Swainston, with Josh McNulty being elevated to the replacements' bench, where he will be joined by Dino Lamb who has come in for Merrick in the match-day 23.