I was just looking, and Blake Smith had played in one game (for less than a minute) at this point last season. Now, we can argue over whether he was ready for significant playing time or not last year, but he did make valuable contributions in important games last year.
Meanwhile Martinelli was a known quantity last year at this time but had only made it to 25 minutes once. Pretty clearly he was ready to go when he needed more time. If you go back to his freshman year, he'd played in just three games - for a little over 20 minutes total - in the non-conference schedule. Barnhizer's trajectory was similar, with just three games for 19 minutes in his freshman year going into the B10 season.
Both Martinelli and Barnhizer ended up playing a bit more in the B10 games in their freshman years (Martinelli more so, but that was likely due to Barnhizer's injuries) than they did in the pre-conference schedule. While they weren't world beaters, at least they could come in.
FWIW, Windham has played 10 games (150 minutes) and Jello has played 11 games (103 minutes). I think it's safe to say that if we're forced to use those guys extensively, NU may suffer due to losing the stars ahead of them, but they've at least had enough significant game experience to be able to step in and contribute.