The 23-year-old, who joined the Gable Endies after impressing in the Lowland League for Stirling University, will return on loan to Montrose until the end of the season, having scored seven goals in 27 appearances so far in 2019/20.
Links Park boss Stewart Petrie told the club website: "I am delighted for Blair to get this chance at full-time football with such a good club and it is great to have him back on loan.
"We always knew he was destined for bigger things and it spoke volumes about Montrose and our increasingly strong connection with Stirling Uni that Blair chose to join us in the summer, when he had other offers on the table."
