In the summer of 2006, Strettle joined the Harlequins from Rotherham, and made his club debut in the pre-season friendly against ASM Clermont on 6 August of that year.

He was also named in the Sky Sports Dream Team for the Guinness Premiership season 2006–07, along with fellow Harlequin and England hopeful Mike Brown.

Unfortunately, he came down with food poisoning along with other members of the squad, which prevented him from starting in England's 58–10 record defeat to South Africa.

[5][6] He returned to play for Harlequins after recovering from the injury that put him out of the 2007 Rugby World Cup and was called up to the England squad for the 2008 Six Nations Championship.

[14] Strettle is an aficionado of Football Manager, and sees himself as having the knack for "picking up players on the cheap and turning them into the new Rooney or Henry".

This was an idea he floated to the Saracens coaching staff after a serious injury to flyhalf Derick Hougaard and resulted in Venter bringing in Owen Farrell at 10.

He recently boasted of his ability to turn West Ham into a top European team within 2 to 3 seasons, while also stating that he was a "world class football manager".