It marked the latest moment of a turbulent season for the 24-year-old, who has been played as a central striker, winger and central midfielder by Mikel Arteta for his club before this sojourn into the defence.
"We have different formations depending on how high the opponent stands and defends - Kai won't always be in that position," Nagelsmann told RTL before the game.
"I have a lot of ideas for him because he is an exceptionally good footballer. It's a very good option. He won't always play as the classic left-back that you might know."
— Viaplay Sports UK (@ViaplaySportsUK) November 18, 2023
The Germans, racing to get a strong team together for next year's tournament on home soil, still have a way to go and their leaking defence remains a major cause for concern.
The Turks, already qualified for Euro 2024, looked sharp with thousands of away fans backing them, but the hosts eased off after a strong start and an early lead, and the result will do little to fuel German fans' expectations for the tournament next year. Nagelsmann, who took over from Hansi Flick, enjoyed a winning debut in October away to the United States before drawing against Mexico.
Germany took a fifth-minute lead when Havertz converted a Leroy Sane cutback in front of a sold-out 70,000 crowd. Sane came close to scoring himself when he saw Turkey goalkeeper Altay Bayindir out of position but his low drive sailed narrowly wide.
The visitors made the most of a string of defensive errors to hit back and they cut the deficit through Ferdi Kadioglu's powerful shot after he latched on to a deep cross from Abdulkerim Bardakci in the 38th minute.
Turkey drew level through former Bayern Munich youth player Kenan Yildiz in first-half stoppage time after the 18-year-old was left completely unmarked at the far post.
Niclas Fullkrug levelled three minutes after the restart with a low shot following Florian Wirtz's solo run for his 10th goal in 12 internationals for Germany but the Turks refused to settle for a draw.
Salih Ozcan hit the post and they earned a 70th-minute penalty for a handball by Havertz which Yusuf Sari converted.
Additional reporting by Reuters