Lewis Bradley and Chris Bell from Huddersfield Rugby Union Club are playing for Yorkshire in the National Under 20 County Championship semi-final on Sunday.
It means Bell misses the National II North clash with Caldy at Lockwood Park on Saturday, a match in which Bradley completes a two-match ban (reduced from three).
Lewis Workman could also be wearing county colours against Hertfordshire at Sandhill Lane, Selby (2.30), so Lockwood Park head coach Gareth Lewis will have to make a late selection.
Huddersfield have a string of injuries, including Adam Malthouse (shoulder), Adam Tamanis (neck), Joah Bradley (shoulder) and Henry Ward (also shoulder).
In addition, Henry Walker and Gavin Rhodes are unavailable and Joel Hinchliffe is returning from holiday.
Lewis has rewarded Tom Baxter for his solid performances with a call-up.
Field were beaten 22-10 at leaders Macclesfield last time out and Lewis explained: “Last week was a great second half and we were hoping to maintain the momentum against Caldy this weekend.
“Caldy have had another excellent season and really are an established club in this league.
“Nick Royle has scored another hatful of tries for them and we know we must defend well against him and the many other attacking threats they possess.
“However, we performed very well two weeks ago beating Luctonians and, if we can reach those levels again, I’m confident we will be in with a shout of victory.”
Huddersfield: (from) Hodson, Kanouros, Hodgson, Owen, Fletcher, Hinchliffe, Jeffrey, Battye, Thornton, Baxter, Thompson (A), Birkhead, Rhodes (N), Hoyle, Parfitt, Thompson (D), Sanderson, Black, Grainger, Workman.<p/>