Jagielka said manager David Moyes was well versed in getting the best out of a small squad and they needed to focus on ensuring there was no drop in performances.
"It's not like we have had massive squads in the past, it is par for the course that we have 16-18 senior players," he told the Liverpool Echo.
"It will test our squad because it is always a busy time but the manager knows what he is doing and if someone needs rest then I'm sure they'll get it.
"We just have to get some much-needed points to keep us at the top of the league.
"We don't want to be looking too far ahead - we normally have a good second half to the season but that is not a guarantee.
"The manager will be nervous now because this is where our season normally starts.
"It would be nice to put two parts of the season together rather than just one."