The Gulls, who lost in last season’s play-off final, are 10th in the National League but can’t make the top seven this time around.
Johnson is looking forward to building a new group in the summer but some of the current crop could still earn themselves new deals with some strong performances, starting with the visit of the Spireites this weekend.
"We'll just take each game as it comes and get the boys to show what they're made of,” Johnson told BBC Radio Devon.
"Have they got what they think they've got? The pressure's off a little bit, but you still need the work rate to make sure that you bring out your best game, so I'll be looking to see whether the ones that are 50-50 maybe can show me that they're worthy of another contract."
Although they have nothing to play for, Johnson wants his side to put on a show in front of the BT Sport cameras.
“We have still got a big say in who gets in the play-offs at the moment and maybe who wins the league,” Johnson added.
"We will still be giving it our all, that is the nature of the beast here.
"We are playing for personal pride and a club pride, especially when you are on the TV. In football you need as many people as possible to see your club in a positive light, whether it be players or adding to next year’s season tickets. You have got to showcase your club on and off the field and that is very important to me.
"We have just finished short, as far as the play-offs are concerned, but it would be nice to finish near them anyway, If we can finish in the top 10 then it will be a good recovery from the start of the season. We have picked up a lot of points since the beginning of the season."