The three-time series champion revealed the extent of his injuries on Twitter, posting a bloodied picture of himself sat against a tree.
He has been treated by the Worcester Acute Hospital NHS Trust service for a broken clavicle, multiple shoulder fractures, a broken rib and a collapsed lung.
The tweet read: “Slight shunt today.
“Matt Neal 0 – Tree 1…”
“Basically broken clavicle, multiple fractures to shoulder, broken rib, punctured lung which then collapsed.
“Still enjoying the hospitality of Worcester General, where the staff are absolutely fabulous.”
Aged 53, he is the oldest driver on the grid and is due to begin a record-breaking 30th season in the BTCC - having made his debut in a BMW E30 M3 in 1991.
“I go into 2020 as hungry as ever to win my fourth BTCC title and take it to Colin [Turkington], and of course my own team-mate Dan [Cammish], who continues to impress me with his driving aptitude,” Neal said.
“The Honda FK8 Type R is now a pretty potent package in its third season and I can’t wait to get behind the wheel testing again next month.
The 2020 BTCC season is due to kick off at Donington Park across 28/29 March.