The German centre-back, a linchpin in Xabi Alonso's squad, revealed he had been open with Leverkusen about his decision to seek a new challenge after over a decade with the club.
"I've been completely transparent with the club," Tah said. "There's no set timeline, but they've known my intentions from the start."
The 29-year-old, whose deal runs out in June, added, "I decided not to renew my contract or stay here, and that hasn't changed."
Tah's departure marks the end of an era for Leverkusen, where he rose through the youth ranks to make over 300 appearances since his debut in 2015. With the freedom to negotiate with foreign clubs since January 1, speculation about his next move has intensified.
Barcelona have emerged as frontrunners to sign Tah on a free transfer. Reports suggest the Catalan giants have been tracking the defender for months, with interest dating back to last summer.
Sources indicate Barcelona have urged Tah's agent, Pini Zahavi, to keep them informed before any decisions are made, effectively aiming to secure the player ahead of rivals.
"They've made their interest clear," a source close to the negotiations said. "Barcelona want to ensure Tah doesn't slip through their fingers." The club see Tah as a cost-effective solution to bolster their backline, given his experience and composure on the ball.
While Tah has not committed to any club, Barcelona's proactive approach positions them as favourites. For now, the defender remains focused on Leverkusen's campaign, but his future promises to be a major talking point as the season progresses.