He has impressed Parry in training and could make his debut in Saturday's home clash with Oldham.
Parry said: "Marvin is only a young lad but he's highly thought of at Watford.
"He's a level-headed lad and I think he's mature for his years.
"The first day in training he was a bit quiet, but he's got really good feet and his finishing looked top drawer."
Source: Team Talk
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