On 8 September 2002 he was sent-off following a clash with his one-time flatmate Kyran Bracken in Bath's 28–3 Zurich Premiership defeat to Saracens. Grewcock was initially banned for five-weeks after being found guilty of reckless use of his boot. Bath appealed against the ban; with Bracken's support and new photographic evidence of the incident, the appeal was successful and Grewcock's ban quashed. In March 2003, he was cited by the RFU of two counts of striking another player during Bath's 27–10 Premiership defeat to Northampton Saints on 15 March 2003. Grewcock was found not guilty of both striking charges but the unsporting behaviour complaint, where he was accused of ripping up the scrum-cap of Northampton lock Mark Connors, was upheld and a fine of £500 issued. An eventful season culminated with the receipt of a red card for punching Lawrence Dallaglio, in Bath's 30–48 European Challenge Cup final defeat to London Wasps on 25 May 2003. A post-match disciplinary hearing saw Grewcock suspended for 14 days, with the suspension commencing on 1 June 2003 and consequently ruling him out of the New Zealand leg of England's summer tour of Australasia. Consequently, having originally been named in the original 37-man squad, he was replaced by Tom Palmer.