The ex-Chelsea man will provide a versatile attacking option for Ange Postecoglou in the absence of Asian Cup representative Son Heung-min and Alejo Veliz, who has been ruled out for a couple of months with a knee injury.
Tottenham are also believed to have negotiated an option to make Werner's stay permanent, as the 27-year-old aims for a shot at redemption in the top flight of English football following a mixed spell at Stamford Bridge.
Ahead of Werner's arrival in North London, Sports Mole takes a look at which shirt numbers could be on offer to the Germany international for the second half of the season.
Ever since his maiden campaign with RB Leipzig in the 2016-17 season, Werner has retained possession of the number 11 jersey, also pulling on the same shirt during his two years at Chelsea and for a brief period in the Stuttgart youth setup.
Gareth Bale, Jimmy Greaves, Gary Lineker and all-time record appearance maker Steve Perryman are among those to have sported the '11' for Tottenham, but for the past two-and-a-half years, the shirt has been in the hands of fellow winger Bryan Gil.
The 22-year-old has hardly proven himself as an indispensable member of the Lilywhites setup since joining from Sevilla in 2021, although he is making sporadic appearances under Postecoglou and is unlikely to cede his number 11 jersey at this moment in time.
While Werner has also donned the '11' for Germany, the striker has normally been seen with the '9' on his back for Die Mannschaft, but that number is seemingly off the table while Richarlison - the current incumbent - comes good in the final third for Tottenham.
Alongside the aforementioned two numbers typically reserved for attacking options, Werner was Stuttgart's number 19 when he first started to make a name for himself at senior level, and he also sported that shirt while playing for Germany's Under-17s.
However, Tottenham's '19' is currently off limits, as injury-plagued midfielder Ryan Sessegnon - who made his first appearance of the season in Friday's 1-0 FA Cup third-round win over Burnley - was handed the number upon his arrival in 2019 and has kept hold of it ever since.
In terms of available numbers, Tottenham are currently without a number two or number six due to the recent exits of Matt Doherty and Davinson Sanchez, although either one of those jerseys would be a peculiar selection for an offensive player. In contrast, the number 16 - last donned by Arnaut Danjuma - is a viable option.
Should Eric Dier's proposed move to Bayern Munich go through this month, the '15' would be awaiting its next taker too, while the 24, 25 and 28 shirts are also up for grabs; Ledley King's iconic '26' is expected to remain in unofficial retirement indefinitely.