Following a citing, Grewcock pleaded guilty to stamping on Nathan Bonner-Evans in Bath's 18–16 home Guinness Premiership victory over Sale Sharks on 22 December 2006. He received a one-week suspension for the offence. The same season saw him cited a second time, this time for a punch on Thibault Privat in Bath's 22–16 defeat by Clermont Auvergne in the European Challenge Cup final on 19 May 2007. He was found guilty and suspended for the period 8 June – 15 September 2007 which, taking into account the close season of inactivity, meant that he was suspended from playing rugby for a period of seven weeks, the start of his season being judged to be 4 August 2007. He lodged an appeal against the ban but was unsuccessful.