Murphy played his final game for the club last week against Celtic and Lasley believes his absence will leave a significant hole in the Fir Park front line.
It remains to be seen if the Motherwell boss will be given the nod to bring in another body in the transfer window, but with the team pushing for a second-place finish, Lasley believes the Steelmen could receive a vital boost if McCall was able to bring in a fresh face to replace his former team-mate.
Murphy's sale brought in around £100k for the club but it may also leave them short up front, with the 23-year-old having netted 11 of the 37 league goals the club have scored this season.
And Lasley said: "On the one hand we are all delighted to see Jamie get his chance and make a move, but on the other it is hard to see him go because we know how much quality he brought to the team.
"He is a smashing lad who has come through the ranks. It is to his credit that he was determined the club would get a bit of money for him when he went and we hope that means the manager gets a good bit of it to spend now.
"As a team we are pushing to cement our place at the top end of the league and we are striving to get that second-placed finish. That in itself would generate income for the club, but it may be that we need a wee bit of help to get there."
For the time being there is a chance for managers to get on the telephone and take in other games, given the brief shutdown the Scottish top-flight is about to embark on.
For the players there is a chance of some downtime for a week or so before the rigours of training resume.
It is the first time there has been a break, however short, since 2003, and Lasley is hoping that it is something that could become a permanent fixture on the SPL calendar.
"I hope it is here to stay," he said. "I do think it gives everyone a break, even if it is only a wee while.
"You still come back feeling that wee bit refreshed and ready to go again for the big push between now and May.
"There are a lot of games and it is just good to get a chance to get over wee knocks and bruises but, equally, it is also good for supporters to get a break.
"Financially this time of year is always difficult because we have just come out of the festive period and it is a big ask to expect supporters to keep putting their hand in their pocket.
"Once we get back into the games then hopefully they will also be looking forward to getting back out and getting behind us.
"We finished the season strongly last season and the aim again now is to keep moving forward and really try to get that second spot."