The talented midfielder went into last Friday night's qualifying final under a cloud after suffering a foot injury late in the season.
After nine disposals in the first quarter Johnson appeared hampered by the foot problem and his output in the final three quarters was limited.
Bartel said Johnson was good enough for the club to back him in if he declared himself ready to play.
"If Stevie is nearly right you play him, because he is right," Bartel said.
"We know how hard it is to carry underdone guys in a final, so I'm sure if he said he was right and he passed everything then you would have to play him because he is in our best 22."
Bartel said that despite its poor performance up forward against the Hawks the team did not have to do anything drastic.
"We have been pretty solid all year as a whole. We probably just have to kick the ball better inside 50," he said.
With Geelong on the back foot after its loss in week one of the finals, the absence of ruckman Hamish McIntosh to injury and clouds hanging over Johnson and forward Allen Christensen, who missed the first final with a back problem, it is under pressure.
However Bartel – who enters a club record 26th final – said it was under no more pressure than North Melbourne.
"Everyone's keen to put pressure on somebody but it is on everybody in a finals game; that is what makes finals exciting. The Kangaroos will probably be feeling pressure because they want to play in a Grand Final and keep going and so do we," he said.
Geelong expects North Melbourne to play attacking football and be brave on Friday night. Bartel was impressed with the Kangaroos' performance against Essendon when they came back from 33 points down early in the second half to record a memorable win.
"They run really hard. They like to take us on. They share the ball around a fair bit and they are very dangerous too with their forwards," Bartel said.
He expects Mark Blicavs to handle the responsibility of shouldering the ruckwork against Todd Goldstein as well as he has handled every challenge so far in his career.
"He [Blicavs] has never seemed too overawed by anything he has done at AFL level," Bartel said.
Bartel is not concerned with recent history that suggests it's extremely difficult for the qualifying final loser to win the premiership. He says his sole focus is on Friday night's challenge.
The good news for Geelong is that 26 of the past 28 qualifying final losers have won their semi-finals, the Cats have not lost to North Melbourne at the MCG since a famous final back in 1997 and they have beaten the Kangaroos both times in 2014.
