After an unsuccessful trial with Dundee United and turning down a contract from Northampton Town, Pinault signed a one-year contract with League Two club Grimsby Town on a free transfer in July 2004. Pinault was a regular in the team during the 2004–05 season, making 47 appearances and scoring seven goals, but his relationship with manager Russell Slade deteriorated after he was "singled-out for criticism" by Slade for his defensive performance during a 2–2 draw with Notts County late in the season. He was released at the end of the 2004–05 season. In 2006, Pinault's remarks about his time at Blundell Park were chosen as one of BBC Sport's Quotes of the Year:
