English domestic cricket's new concussion substitute rule is being used for the first time after Lancashire bowler Joe Mennie was struck on the head by the ball in his county's match against Worcestershire at New Road.
Fears about Mennie's well-being were heightened because he suffered a skull fracture in an accident in the nets only 18 months ago.
Danny Lamb, a 22-year-old allrounder, will replace Mennie for the final two days of the four-day game.
Mennie, the 29-year-old Australian seamer who is the county's main overseas player this season, suffered an impact to the right side of his head in his follow-through bowling to the hard-hitting New Zealand batsman Martin Guptill on day two of the County Championship match.
Guptill, who struck four sixes in a debut century for Worcestershire, hit the ball into the ground and Mennie instinctively raised a hand to protect himself but succeeded only in deflecting it towards his temple.
He fell to the ground and initially lay motionless amid considerable concern for his wellbeing. Mennie suffered a skull fracture in January last year with minor bleeding to the brain after he was hit in the nets while practising with his Big Bash League team Sydney Sixers, although he recovered well and was playing again within two months.
Happily, after attention on the field here, he was able to walk off unaided but after further assessment in the dressing room it was decided he would take no further part in the game.
Lancashire then approached Richard Ellison, the ECB's assigned Cricket Liaison Officer, to ask for permission to use a substitute under the new rule, which allows for a player who has suffered a head injury to be replaced by a like-for-like player who can take full part in the remainder of the match.
Mark Chilton, Lancashire's assistant head coach, said: "We do not know for sure whether he has concussion until he undergoes further tests later but it was not a glancing blow.
"Although the ball was hit into the ground and Joe stuck out his hand to stop it, the ball deflects into the side of his head with enough impact that it has left an impression of the seam.
"Obviously that caused immediate concern for everybody and although he was conscious at all times he was pretty shaken and has a sore head.
"We were aware of what happened to him last year but there would have been the same concerns irrespective of that.
"Accordingly, we expressed our concern to Richard Ellison, the CLO, and told him that we were not confident of Joe's fitness to complete the game and he agreed to the use of a substitute.
"We have Saqib Mahmood here and Toby Lester as the reserve seamer in the squad but Saq is not fully fit and Toby is an opening bowler who bats number 11.
"Joe, of course, bats at number eight and we are able to use a like for like player. Danny fits the bill because he bats a bit as well as well as bowling and he will join us once he can travel down here from Manchester.
"Joe will have further tests this evening to assess whether he has suffered concussion but already seems much better and hopefully there is no lasting damage."
Lamb, from Preston, will be making his first-class debut. He played in two One-Day Cup matches last year and made 30 runs and took 3-30 in his one Twenty20 appearance, against Leicestershire at Liverpool.