But with the Swedish league season having finished five weeks ago, the midfielder will need more time to regain full fitness ahead of his bow in English football.
Latics boss Paul Jewell said: "Andreas trained yesterday and I think he found it pretty tough as he hasn't played for five weeks.
"The session was quite high tempo and he will need more of that to get match-fit – he's got to have a mini pre-season if you like.
"Saturday's game at Rotherham is far too early for him.
"Although he is a naturally fit lad, he has to adapt to a different culture and environment, together with a different style and tempo of football.
"So we will give Andreas every opportunity to settle in by getting him as fit as we can."
Johansson enjoyed his first run out with Latics and hopes the switch will strengthen his chance of regular call-ups to the Sweden squad, the last of his 12 caps having come a year ago.
"I had to choose between Wigan and an opportunity to go to Rosenborg in Norway," said the 26-year-old.
"There was more interest from Wigan and I felt that was very important.
"They had seen me play a lot more and were interested at an early stage in getting me over to England.
"I'd played for five years in Stockholm with Djurgardens and felt I wanted something new.
"It's a good challenge to come here and with Wigan second in the Championship table, it says to me they are a good team.
"I talked to my friends in Sweden about the transfer and they all said it would be a good move for me, and I also spoke to Olof Mellberg at Aston Villa.
"While he didn't know too much about Wigan, he said the Championship was a really good league to play in and I should give it a try."
Johansson is the first player Jewell has signed from abroad during his time in charge at the JJB Stadium.
Jewell said: "Trying to get good players in this country or anywhere isn't easy, so we decided to have a look aboard and see what was available.
"Andreas wasn't the only one we looked at, we went to watch plenty of other games but nothing really caught our eye.
"Someone recommended Andreas to us, we went to watch him a couple of times and we liked what we saw."
Jewell hopes Johansson won't be his only new addition in the near future.
But Danish midfielder Stig Tofting isn't one of them, although the former Bolton man is training at Christopher Park this week.
Jewell said: "Stig is just here as my minder!
"Actually, he is a good friend of Per Frandsen and staying with him at the moment, so Per asked me whether he could come and train with us.
"That is all it is, he's not here on trial and we are not going to be taking him.
"I would like to bring one or two more players in and we've made a couple of enquiries which we're waiting for answers on."