Jack Clarke became the club's fourth January addition earlier this week, the winger signing on loan from Tottenham Hotspur until the end of the season.
Another striker is known to be the club's main priority; talks ongoing with Jermain Defoe after he left Rangers to become a free agent earlier this month.
The head coach says he is happy with his squad as it is but has strongly hinted that they will look to recruit further.
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"It's looking good and I'm very pleased with the business we've done," Johnson said.
"Everyone has done a great job in that sense.
"We're still in the mix. I'd be more than happy if this is all we had but at the same time there are a couple of options and positions that we could do with bolstering."
Denver Hume's departure has left some supporters eager to see the club recruit further at full back, given that Niall Huggins is out until March with a back injury and that 19-year-old Trai Hume has yet to make his debut following his arrival from Linfield.
There has also been some concern voiced about the depth in central midfield, with Luke O'Nien another player injured until March and Carl Winchester often required to play right back so far this season.
The Echo put those two positions to Johnson, who confirmed that they were areas in the club's thinking.
"I think there's definitely an argument for both of those," he said.
"Obviously we've spoken about a forward to lighten the load on Ross Stewart until Nathan Broadhead is back.
"That's something we could consider.
"We've got five loans now, so if we were to bring in another there would be one who couldn't be in the matchday squad [once Broadhead is fit]. It's also undoubtedly true that it's harder to do permanent deals in January.
"We just have to make the right choices and the beauty of our squad is we have got players who can cover in numerous positions.
"We do want to bring in a solid number but at the same time, if you have too many it can become a little bit disjointed and fractious.
"It's always a delicate balance between making sure you have the depth in the positions, the squad number and the quality required to win games."
Bar any unexpected developments the club were not expecting to secure any additions before Saturday's clash with Bolton Wanderers, meaning that they are likely to be active on deadline day.
"We're not necessarily expecting a busy day, but we'll certainly be busy in terms of our due diligence," Johnson said.
"We know our place at the table, if you like, and it's often the case that players become available because of the way things move.
"I'm very confident that we're ready in a good position, and the support will be there if a player we want becomes available."