Neil Lennon has given Hibernian's Ladbrokes Championship title hopes a boost in recent weeks by making two impressive signings ahead of the visit of United on Friday night.
Hibs brought in Kris Commons from Celtic on a four-week loan deal which could be extended, and signed former Motherwell winger Chris Humphrey from Preston until the end of the season.
United are looking for a striker as a priority and were frustrated in attempts to sign Conor Sammon from Hearts before losing top spot to Hibs at the weekend.
But United's 1-0 defeat at Dumbarton was their first defeat in 15 matches and McKinnon was not tempted to panic buy ahead of their eagerly-anticipated clash at Easter Road.
McKinnon said: "We are searching and moving forward with that
It's all about timing, I don't think there will be anything concrete in the coming days
"It's important because we need that shot in the arm
The squad has done very, very well but we recognise we need to improve the quality and the competition in certain areas
"Hibs have done really good business
Kris Commons is a top player, he has played Champions League football, very experienced and is an excellent football player, and they have signed the boy Humphrey too.
"They have stated their intentions, there is no doubt about that, and quite rightly so.
"We just need to be patient and hopefully add someone to our squad
But I won't make any rash decisions.
"It doesn't affect me
I have to make sure whoever I bring in is right for the squad good bunch hard-working and whoever we bring in has got to fit into that.
"I wouldn't just bring someone in because they have done this and done that.
"I will certainly work hard on it but it doesn't up the ante
Fair play to Hibs, they have worked hard to improve their squad and they have been able to do it quickly
It might take us more time but we will hopefully get there."
United have taken four points from Hibs this season and McKinnon believes his team can continue to exceed expectations.
"Hibs are a good side, they got to two cup finals last season and won one, and have strengthened their squad," he said
"It will be a tough game but we have good players and talented boys at our club as well and it should make for a good game."
Source : PA