diff --git a/keyboards/haverworks/theseus75/config.h b/keyboards/haverworks/theseus75/config.h
index f8110bb92fa..332c98bb7b4 100644
--- a/keyboards/haverworks/theseus75/config.h
+++ b/keyboards/haverworks/theseus75/config.h
@@ -12,7 +12,6 @@
 #define ID_PIN A13
 #define USBSW_PIN A14     // Switches the hub input/output with the MUXes
 #define PSW_PIN A15       // Turns the power routing to the USB-C port on/off
-#define SPLIT_HAND_PIN B9 // The MCUs probe a pin to determine if they are left or right side. high = left, low = right
 #define BUS_B_PIN C13     // Tells the hub to be bus-powered or self-powered (which in turn tells the clients to use 100 mA or 500 mA)
 #define USB_VBUS_PIN C15  // Only the master side will have VBUS present at power-up (used to determine master/slave)
 #define USBPD_1_PIN F0
diff --git a/keyboards/haverworks/theseus75/keyboard.json b/keyboards/haverworks/theseus75/keyboard.json
index c09e1475584..60f791ae9d7 100644
--- a/keyboards/haverworks/theseus75/keyboard.json
+++ b/keyboards/haverworks/theseus75/keyboard.json
@@ -129,6 +129,9 @@
                 ]
             }
         },
+        "handedness": {
+            "pin": "B9"
+        },
         "matrix_pins": {
             "right": {
                 "cols": ["A10", "A9", "A8", "C6", "B15", "B14", "B13", "B12", "C14"],