In a post on Twitter, the 21-year-old thanked all at the club for his time at the Keepmoat, which ends after almost three years.
He wrote: “Thank you to everyone at Doncaster for the past 3 years!
“It’s been a great 3 years with some unbelievable memories that I won’t forget!
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“Would also like to wish the club, lads, staff and fans all the best for next season! It’s been a pleasure!”
It is understood boss Grant McCann opted against offering Beestin a new deal due to the lack of game time he would be able to offer the youngster.
Beestin was loaned to Chesterfield earlier in the season, making five appearances, and was given an opportunity to earn himself a new deal when returning to Rovers.
He did impress McCann, who admitted he had finally witnessed the ability he had been told Beestin had shown prior to the manager’s arrival last summer.
But McCann ultimately conceded it would be detrimental to Beestin’s progression if he were to remain with Rovers.
The forward arrived at Rovers in August 2016 from Tadcaster Albion and their affiliate i2i Academy.
He scored on his debut in the Checkatrade Trophy against Mansfield Town before going on to make eight appearances that season.
It was in the second half of the 2017/18 where Beestin truly broke through, becoming a regular starter under Darren Ferguson. Arguably the high point of his Rovers career came with a last gasp equaliser in the derby at Scunthorpe in January 2018.
Following the change of management last summer, he found game time hard to come by.
McCann said he felt Beestin needed to settle on a position rather than continue to show his versatility.
Though he played in all three Checkatrade Trophy matches, he made only two league appearances before his loan to Chesterfield.
He departs having made 50 appearances for Rovers, scoring three goals.
Rovers are expected to confirm their retained and released list before the end of the week.