Stewart has been in isolation since his car struck and killed Kevin Ward Jr. in an Aug. 8 sprint car race.
''I didn't feel like it was the right time (to call him), but we're all praying for him,'' Gibbs said. ''We all love Tony. I love what he did for us here. We all know he's a racer's racer, and he's big for our sport.''
Stewart drove for Gibbs from 1997 through 2008, winning Cup titles in 2002 and 2005 driving for Joe Gibbs Racing. He left following the 2008 season when he was offered an ownership stake at Stewart-Haas Racing.
Gibbs said Tuesday he learned early in his tenure that sprint car racing was Stewart's passion and the car owner had to accept Stewart's participation in other series. He said all team meetings were disrupted by Stewart updating the group on his latest adventures outside of NASCAR.
''I had to spend 30 minutes listening to him how he won a dirt late model race, and I wanted to go, 'I don't care, OK?''' Gibbs said, laughing. ''But he was so excited. I came to the conclusion that was him - for him to be happy and doing the things that he wanted to do, he was going to be racing.''
Gibbs said Stewart was a valuable member at JGR. When another employee was struggling to cover the cost of adopting a child, Stewart gave him the needed funds. He hoped as Stewart continues his recovery process, more examples of Stewart's softer side will emerge.
''Tony's got great courage. He's smart. He loves this sport. He's totally focused on it. He doesn't have distractions,'' Gibbs said. ''He's very important to our sport. This is a horrible thing to have happen for the Ward family, for him.''