Weir has been hugely impressed by Edinburgh scrum-half Laidlaw. who was arguably Scotland's man of the tournament, which ended with a 23-16 defeat to France in Paris on Saturday night. His goal-kicking was near-flawless while his work at the breakdown was terrier-like as he harassed his forwards at the same time as organising his colleagues in the backs.
Now Weir hopes the displays were enough for Laidlaw to earn a call from Warren Gatland ahead of this summer's tour of Australia and consideration as an alternative to Welshman Mike Phillips, favourite for the starting scrum-half slot. Weir told Press Association Sport: "For me, a lot of credit has got to go to Greigy."
He continued: "He's kicked the goals really well. He's bossed the forwards and helped out marshalling the backs as well. His leadership skills at the back of the base, his voice in defence, they have both been outstanding.
"He gives me a lot of guidance at 10 but also takes a lot of the responsibility himself by kicking from source when he collects the ball.
"He's been a key man for us this season and I think he's got a great shout for a Lions place."
Laidlaw had been filling it at stand-off for club and country before Blair - capped 85 times for his country - announced he was stepping down from the international game.
The move back to number nine has suited the 27-year-old but Weir believes the stint at fly-half was beneficial.
Weir said: "Greig understands how to do both roles just as well. He's benefited from his spell at 10. He already had a huge rugby brain being a Borders boy but he's an immensely talented guy and has really rallied the troops this year."