The 20-year-old former Worthing loanee has been given a spot in Eddie Jones’ squad along with ex-Raiders pair Joe Marler and Joe Launchbury.
Marchant had a year-long stint with Raiders two seasons ago as part of his development from Harlequins.
In that time, Coulson felt Marchant’s attitude and ability left him in no doubt he would go onto great levels in the game.
He said: “Joe’s attitude from the first moment he came down to us was incredible.
“He was injured early on in his time here but played a couple of games in the second team before forcing his way into the first team.
“Joe was such a humble guy and worked incredibly hard in his time with us.
“He really brought into everything here at Worthing and, to be honest, I’m not surprised to see him earn this call.”
The England squad will meet at The Lensbury Hotel on Saturday for a two-day training camp and planning meetings ahead of series against Australia, Fiji, South Africa and Argentina later this year.
Speaking ahead of the two-day training camp, head coach Jones said: “This camp sets the scene for November.
It’s important to catch-up with the players prior to the start of the season and continue to put our plans in place.
“We’ll use this time to reset and review each player’s goals so they’re clear on what is expected of them between now and when we meet up again in October.
“It also gives us an opportunity to meet and assess some new players and ensure they are familiar with the England set-up.
“The long-term strategy for England is to develop a side who can be the most dominant team in world rugby, so we’ve chosen a number of new faces to attend this camp on the form they have shown recently or the potential we see in them.”
England will announce a final 45-man elite player squad on September 30 ahead of their Old Mutual Wealth Series, which starts with a game against South African at Twickenham on Saturday, November 12.
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