Motherwell have signed right-back Brodie Spencer but manager Stuart Kettlewell admits he faces a major challenge to alleviate the lengthy absence of strikers Mika Biereth and Jon Obika.

Kettlewell has ruled Obika out until December with a hamstring injury and on-loan Arsenal striker Biereth will likely be missing until mid-November after suffering a knee injury against St Mirren.

Kettlewell was already well down the line in signing Spencer from Huddersfield on loan following the departure of Barry Maguire on loan to Kidderminster but he is limited in what he can do in the transfer market given the club’s spending increases in previous seasons.

He said: “I have always spoken about trying to run with four strikers minimum so that is a huge blow with the news on Mika and Jon Obika, it puts us down to two senior strikers in Theo (Bair) and Conor (Wilkinson).

“Jon Obika, we are probably looking at December. It’s a difficult one but it doesn’t change the situation for me. For us to do any more business, we are in a situation where we are one in, one out.

“It’s been a real tough week and a tough week without a blank canvas just to be able to pick up the reins and go and bring players in. But we will continue to work away and see if we can make the situation slightly better.”

Kettlewell declared 17-year-old Mark Ferrie was now “striker number three” while wide player Joe Efford can also play up front but has only had about 15 minutes of action since returning from a long-term thigh injury.

Immediately after Saturday’s Viaplay Cup defeat, Kettlewell accused Charles Dunne of making an “absolutely horrendous tackle, two-footed and straight-legged” on Biereth.

In response, the former Motherwell defender claimed he won the ball but “unfortunately slipped” and caught the Denmark Under-21 international. Dunne has contacted Biereth to apologise.

When asked if he had a different opinion on studying the footage, Kettlewell said: “My opinion hasn’t changed.

“One of the things I heard was that he won the ball. What everyone needs to understand – and I need to stress, these aren’t my rules, anyone that watched me play football will realise I picked up more red cards than anybody else and was involved in more crazy challenges than anybody else – but the rules have changed.

“I have lost count of the times I have been told by officials that it doesn’t matter if you win the ball. If you are off the ground, coming in at pace, putting an opponent at risk of injury, coming off the ground, all of those aspects, I was led to believe that was a red card.

“I hear some ridiculous arguments of ‘ah, but he took the ball’… If you have to come through the player and both your legs are wrapped around the standing leg…

“I understand that Charles Dunne has reached out and apologised for the outcome of the challenge so I tip my cap to him and say fair play in that sense. But it doesn’t change the situation that it leaves us short at the top end of the park.”

Spencer moved from Huddersfield on a season-long deal after signing a new contract with the Yorkshire club. The 19-year-old is a full Northern Ireland international and has made six first-team appearances for his club.

“Brodie is a real quality player with bags of potential,” Kettlewell said.

“I think it says a lot when the parent club offer a player a new deal before loaning him out. It shows their real desire to see the player grow and I think Brodie will do just that.”