The Swede has been on international duty since his deadline-day loan from Roma, and may not be able to face Peterborough United at Bramall Lane. He is one of a number of doubts for the reset side.
“We have not had the opportunity to start working with Robin – new rules, Covid, Brexit. I cannot give you an answer if I can use him immediately, I may have to wait a bit more,” said manager Slavisa Jokanovic.
Olsen was one of three deadline-day signings along with Morgan Gibbs-White and former Barnsley midfielder Conor Hourihane. Centre-back Ben Davies also joined in August – like the other three, on loan – and Jokanovic has asked the club to add free agent Adlene Guedioura and is planning a more prominent role for 21-year-old forward Iliman Ndiaye.
Two points from this season’s first five Championship games points to a hangover from their Premier League relegation.
Jokanovic’s comments about Hourihane apply to all the new faces.
“He’s a guy who wasn’t part of our squad in the last 15 difficult months for us,” said the Serb. “He is coming with a clean mind to try and make himself an important part of the team.”
There could also be different roles for some after Jokanovic targeted wingers in the window but missed out on Amad Diallo, Yann Karamoh and Alex Collado.
“The transfer window is done,” he said. “This is my team, my tools, and we need to fix things and try to give the team clear information.
“We tried but for different reasons we weren’t able to finalise deals for some wingers with different characteristics so we need to adapt and look at players in different positions.”
Ndiaye made his Blades debut as a substitute in caretaker manager Paul Heckingbottom’s first game, in March, but his only appearance since was against Derby County in the League Cup, also from the bench. He could be a wide option.
“Since I’ve been working with him he’s impressed with some qualities I was missing in my team,” said Jokanovic.
“He’s a guy who can play between the lines, who is looking to play forward and can assist and finish the action. Worse or better, he’s definitely different to the players in my team and he’s at an optimal age to take responsibility to compete at senior level.
“He’s good on the training ground, we’ll see how good he can be on the pitch.”
On 35-year-old former Middlesbrough midfielder Guedioura, Jokanovic said: “He is a guy who is really positive in the dressing room. He knows a lot of the players and the competition very well and he is an African champion.
“I consider it an important step. I’m in favour of signing him, I’ve given the green light.”
David McGoldrick is a doubt for tomorrow with the back injury which kept him out at Luton Town, whilst Sander Berge is “touch and go” after testing positive for Covid-19 when he joined up with Norway and Davies has a foot problem.