The Football Association has approved the headguard Petr Cech is to wear on his return from a fractured skull.
Cech could make his first appearance since recovering from a serious head injury suffered against Reading back in October, returning for Chelsea's game at Liverpool on Saturday.
Although Cech is now thought to be ready to make a playing return, he will have to use protective headwear until given the all-clear by specialists.
Referee Rob Styles, who will officiate Saturday's game, has inspected the headguard and given it his approval, according to the FA's head of senior referee development Neale Barry.
"As headguards are not part of the players' 'basic compulsory equipment' as set out in the laws of the game, it's essential that they are safe to wear," said Barry.
"This headguard is soft in construction with padded areas of dense foam all over to protect the head of the wearer. It covers the ears but there's a hole on each side so that his hearing is unaffected.
"The helmet could cause no risk to the safety of either the wearer or any team-mate or opponent of his whilst being worn. It has a Velcro under chin strap and no extraordinary areas on the helmet that could cause unnatural deviation of the ball if it were to either strike the helmet or if the wearer were to head the ball."
While Jose Mourinho has yet to confirm whether Cech will start at the weekend, one player who will definitely not feature is left-back Wayne Bridge.
The England international has suffered knee ligament damage and will be out of action for at least the next fortnight.
"Petr Cech is fine. He is ready. I cannot tell you if he is playing or not because the goalkeepers have to be the first ones to know my decision, but he is ready," said Mourinho.
"We have a new injury with Wayne Bridge. Again a knee ligament, not a big deal but a couple of weeks out. He is an important option for us but now he is out too.
"Ashley Cole is back from suspension but nobody else is back and Makelele is suspended."