Malan, who won three Test caps for South Africa in early 2020, re-signed for the summer after helping Middlesex secure promotion at the end of last summer but has struggled for form. He managed 221 runs at 14.73 across his eight Championship fixtures, with more ducks (five) than half-centuries (two).

He also played eight games for them in the Blast, scoring 206 runs at a strike rate of 137.33, and did not feature in their One Day Cup campaign, with opportunities instead afforded to younger players. He has now returned to South Africa to captain Boland in domestic cricket.

Alan Coleman, Middlesex's director of cricket, said that Malan "would be the first to admit that this season has been a struggle for him on the field". He added: "It most certainly isn't through lack of effort and hard work on his part however, sometimes things just don't work out."

Middlesex, who sit third-bottom in Division One and are locked into a relegation battle with Kent and Northamptonshire, confirmed in a statement: "[We are] now looking for a replacement to feature in the run-in to the end of the season, with four crucial County Championship matches remaining."

Surrey are 17 points clear of second-placed Essex heading into the final month of fixtures, and will be without three fast bowlers on England duty in Gus Atkinson, Sam Curran and Reece Topley - though Curran and Topley have featured in one Championship match between them this season.

Roach said: "Surrey is a second home for me and I'm looking forward to getting back down to business ahead of three massive games. We know what the goal is for the team and I'm going to give everything to help achieve it."