"The 19-year-old young forward, who has recently had a loan spell with York City, has joined the Seadogs in the promotion push, with Hull City willing to extend his loan should Boro make the play-offs."
The York-based teenager made his Tigers first team debut in August 2021 after coming through the Hull City Academy since he was 11.
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Boro boss Jonathan Greening said: "We were keen to get Will to Scarborough earlier in the season, however this didn't quite work out".
"Will is here to provide us with more options in the final third as we strive to be more clinical."
Jarvis is available to play tomorrow at Atherton following NPL and FA approval.