Jack Brooks, the Somerset seamer, has become county cricket's first Covid-19 replacement after Lewis Gregory was ruled out of the final two days of their Championship fixture against Middlesex.

Gregory, who himself contracted Covid while playing for Islamabad United in the Pakistan Super League in March, was replaced in the Somerset side ahead of the third day after his girlfriend reported symptoms of the virus. It is understood that she has returned a negative lateral flow test but is waiting for the result of a PCR test. If that test is negative, Gregory should be available for Somerset's fixture against Hampshire at the Ageas Bowl next week; however, he will play no further part in the Middlesex game.

"Somerset County Cricket Club can confirm that Jack Brooks has been made available as a Covid-19 substitute for the remainder of the current LV= Insurance County Championship match against Middlesex at the Cooper Associates County Ground," a club spokesperson said.

"A member of Lewis Gregory's private bubble was feeling unwell this morning and has taken a lateral flow test. This test proved to be negative, but protocol dictates that until the results of a further test have been received, Lewis will remain in isolation as per government guidelines."

The ECB's Covid replacement regulations dictate that a "like-for-like" replacement should be used where possible, and the nomination of Brooks was approved by Wayne Noon, the match referee. Gregory took 2 for 87 in Middlesex's first innings, and was yet to bat in Somerset's response.

Brooks is the first Covid replacement used in county cricket, and the second in first-class cricket overall after Auckland's Ben Lister. Nick Gubbins, the Middlesex batter, was withdrawn from a fixture in the Bob Willis Trophy last summer to self-isolate, while Jordan Cox of Kent missed a game after breaching protocols by taking a photo with a fan.

Matt Roller is an assistant editor at ESPNcricinfo. @mroller98