The former Hampshire batter played three One-Day Cup matches with Yorkshire and is available for the final four games of the Championship season
Sam Northeast has joined Nottinghamshire's LV=Insurance County Championship title bid after signing on loan for the rest of the season.
The 31-year-old left Hampshire in July and played three times for Yorkshire in the Royal London One-Day Cup.
But following Haseeb Hameed's England recall, Northeast has joined Notts' attempts to scoop their first red-ball title since 2010.
In 180 first-class matches, Northeast has scored 10,727 runs and recorded 25 centuries.
"Sam is a proven run-scorer and a signing we believe will bolster our chances in red-ball cricket during the coming weeks,” said director of cricket Mick Newell.
"With Haseeb Hameed in the England team, the opportunity to add Sam’s experience to our batting line-up is something we believe will benefit our side during the remainder of the season.
"He’ll feature in the second team fixture against Derbyshire this week, with a view to preparing for the red ball action to follow with four important games to come."
The ex-Kent man is available to face Somerset and Lancashire, as well former clubs Hampshire and Yorkshire, in Division One as six sides - Warwickshire being the other - chase the title.