McQuillin was instrumental in Maroons' return to the top flight in 2011 and the RBS Scottish Cup triumph a year later, prompting interim head coach Stevie Scott to hand the 21-year-old the opportunity to train at Murrayfield Stadium as cover for injured elite development prop Alex Allan.
Scott said: "Ewan has fitted in well with the squad and has coped with the increased physicality of professional rugby training."
He added: "It's a fantastic learning opportunity for him to improve as a player by testing himself against some of the top front-rows in the country in training, as well as push for a place in our squad for the remaining three games of the season.
"Scotland's domestic divisions are the bedrock of rugby in this country, so hopefully this call-up will also show other players in the amateur game that, if they work hard on their conditioning and are performing consistently for their club, opportunities for Edinburgh Rugby can come their way."
- Sports & Recreation
- Stevie Scott