The pubs and restaurants group confirmed it is considering selling pubs across its estate which no longer satisfy its core strategy.
Marston's currently operates about 1,482 pubs across the UK and employs around 12,000 people.
The pubs being considered for sale are spread across England and Wales.
A Marston's spokesperson said: "As you would expect, we review our estate from time to time as part of normal course of business.
"We are potentially looking to dispose of a small package of non-core pubs which no longer satisfy our pub strategy.
"In the event of a successful transaction, any disposal proceeds raised will be used to further reduce the Company's debt in line with our stated strategy. A further announcement will be made as appropriate."
Marston's said in May that it was aiming to reduce its net debt below £1 billion by 2025.
The group sold 137 pubs to rival Admiral Taverns for £44.9m in 2019 and 29 to Hawthorn for an undisclosed sum the following year.