Middlesex have loaned opener Tom Lace to Derbyshire for the remainder of the Championship season.
Lace, 20, has yet to make his first-class bow for his parent county but has played six second-string matches and scored 322 runs.
"We wanted to bring in an out-and-out top-order batsman as short-term cover while Luis Reece continues his recovery," said captain Billy Godleman.
"Tom is a good young batsman who is keen to progress."
Middlesex director of cricket Angus Fraser commented: "This is a fantastic opportunity for Tom and a win-win for both parties.
"Tom has had an encouraging season with our second XI and the chance to test himself at a higher level is not one to miss."