Speaking to BBC Radio Humberside, Groves cited the form of the current starting eleven as the reason Jevons, along with Jason Crowe, has found himself without action.
"Phil's been fairly close to it in general," Groves told the station. "He's been around the bench and the team's been playing well on a consistent basis.
"At this moment in time, it's difficult for anybody to get into the team.
"Jason Crowe has been extremely unlucky not to be playing in the team.
"But the players that have been playing in there have done well and they've kept their shirt and that's what we want.
We want competition for places. We want people playing well in the reserves, banging on the doors so that if they're called upon, it's up to them to take the chance."