The 66-year-old German made his debut appearance in 1974 since when he has played 512 times on the tour, winning 42 titles across five decades -- only Severiano Ballesteros has won more.
"I don't know yet (how I will react)," said Langer ahead of his 513th and final appearance.
"I've never said goodbye to anything so far in terms of golf. This is going to be a first experience and I have a feeling it's going to be very emotional."
Langer was due to make his final appearance at this year's Masters but had to pull out when he tore his Achilles tendon.
Five months later, Germany's most successful player said he was still feeling it.
"Things are getting better and better," he told the tour website.
"I'm starting to walk more and more. It's still a bit difficult at times, but golf is not a problem.
"I'm just a little weak. My calf muscle is much smaller on my left leg than my right leg. My balance is not quite there but we'll work on it."
As a former winner, the door is stil open for him to play a final Masters in 2025.
Langer, who grew up 45 minutes from the golf course hosting this week's tournament, last played at the BMW International Open, where he has finished second on five occasions, in 2012.
It is his first appearance at a European Tour event since 2018 and Langer admits the passage of time may make it awkward for him.
"It means a great deal, just to play in front of the home crowd, and hopefully I can make the cut.
"But I hear the golf course is a lot longer than it used to be and that's a challenge for me.
"I'm getting shorter, and the course is getting longer and that's not a good combination."
Langer won the first of his two Masters titles in 1985, when Ballesteros, Raymond Floyd and Curtis Strange tied for second.
In 1993 Langer won by four strokes over Chip Beck.
He also became the inaugural world number one when the official rankings were introduced in 1986.
Last year Langer broke Hale Irwin's record for PGA Tour Champions victories, the circuit for 50 and over pros, when he won twice and holds a record 46 titles.
Langer will tee off on Thursday alongside two other Germans, Martin Kaymer, another two-time Major winner, and Marcel Siem who won his sixth tour title last week in Italy.
