Here is how the O's schedule is shaping up at the end of January, and heading into February.
The 20-year-old has agreed a one-month deal, and is eligible to make his debut for the Rocks this weekend in their FA Trophy tie against Aldershot Town.
Clark, who signed his first professional deal with the O’s in May 2017, has made a total of three appearances for the first team across all competitions this campaign.
This will be the second spell for Clark at East Thurrock, after making 25 appearances for the Essex-based side during the 2016-17 season and scoring three goals.