Oxford United manager Darren Patterson has been forced to wait another 24 hours before finding out the extent of Jamie Guy's ankle injury.

Although the striker went for a scan yesterday on the injury picked up in training, the full results will not be known until later this morning.

It means that preparations for Saturday's home match with Crawley have been disrupted.

Patterson has been considering changing the system his team are playing – but the latest setback has hampered those plans.

The difficulty Patterson faces is that, while he knows the tried-and-trusted 4-4-2 is better for scoring more goals, the players he has in his squad look more suited to the 3-5-2 he has been using in recent games, and even more so following the signing of Paul Evans.

He has used the experienced trio of Evans, Adam Murray and Joe Burnell as a central three who can dominate the centre of the park with their ball-winning skills and passing.

But the wingbacks system relies heavily on the wingbacks pushing forward and delivering quality crosses, and that hasn't always been the case.

Patterson was at least going to try out 4-4-2 again in training this week, with successive home games coming up, though where that would leave the central midfield trio of Adam Murray, Joe Burnell and Paul Evans isn't clear.

After last weekend's 1-0 defeat at Kidderminster, which left the U's with just two wins out of nine so far this season, the U's boss said: "The 3-5-2 system's a decent one if we get the ball and get plenty of width, but without the ball, I'm not so sure."

Surprisingly, because they are creating plenty of chances, goals are again proving a problem.

The U's scored in all of their last seven away games last season, which they finished strongly, and that was when they were playing 4-4-2, though with a slight variation to 4-3-3 at times.

This season Patterson started with 4-4-2 but had to change it when Luke Foster received a four-match ban because he felt there wasn't enough pace at the back with Chris Willmott, who was on his way back from injury, and Barry Quinn.

The arrival of the quick and impressive Karleigh Osborne, on loan from Brentford, does give him the option of returning to just two centre backs, without the need for a sweeper who can cover.

"I'm going to have a look at it this week," he said. "Wingbacks is a system that doesn't really create a lot, it's more of a grinding system. We score the most goals when we play a 4-4-2, but we're struggling for a batch of goals at the minute."

The games don't get any easier. United's next opponents, at the Kassam Stadium on Saturday, Crawley Town went top of the Blue Square Premier at the weekend after beating Mansfield Town 2-1.

Four days later come Cambridge United, who are unbeaten in their four away games so far.