Terrell was due to turn out for Luton Town, while Stevland was set to play for the Cobblers as both young defenders prepare for life outside West Ham.
Both players' contracts run out in the summer, and Terrell says:
"It's a hard life but I've got to keep plugging away.
"West Ham is all I know because I have been there since I was 11, but now I have to start putting myself about.
"It's a big step up and only Michael Carrick and Joe Cole from our youth cup winning side have made it to get a regular place.
"But there are other good players, like Garcia, Byrne, Izzie, Ferrante, and Stev.
"It's going to be hard to make it at West Ham, but I've been training with Luton this week, and Grimsby want me to go back there as well."
Grimsby are also taking a look at Craig Etherington, another of the eight young players whose deals end shortly.
"I am grateful that Luton might be giving me a chance but I haven't spoken to Joe kinnear as he is too busy trying to keep Luton up.
"It's just a case of keeping on grafting and hoping something comes up."
* The U17s clash with Crystal Palace is now off