Darlington could be about to lose Adam Mitchell after the winger began a trial at a League One club.
He will be unavailable for Quakers' game on Saturday at home to Padiham after heading to London for five days with promotion-chasing Brentford.
Darlington manager Martin Gray, who brought Mitchell to the club from Sunderland last month, said: "It's the agreement we've had with him since he came to the club - if he gets a chance to go on trial at a Football League club then we wouldn't stand in his way, so I wish him good luck.
"We did the same with Nathan Thomas when he came to us from Sunderand and he made his debut for Plymouth this week and was man of the match.
"I hope Adam does well down there and gets a contract."
Darlington expect that Mitchell will be able to feature in their remaining league games, plus the play-offs, once he returns from Brentford.
The speedy winger was released by Sunderland having played in one first-team game and has since impressed in four starts for Quakers, scoring once.