After a break, Faith Hill came to the front of the stage with the couple's band (it was a co-headlining date) and explained that her husband was dehydrated. "And I apologise, but I made the decision that he can not come back out on stage", she told fans.
Just prior to singing "Humble and Kind", Tim sang "Shotgun Rider", and appeared to be well, according to video shared by K92.3 listener Ben Johnston.
Her announcement was met with clapping and cheers from the crowd.
A rep for the 50-year-old McGraw confirmed that on-site medical staff responded to help him.
A spokesman for McGraw said of the incident: "Tim McGraw was suffering from Dublin this evening at the C2C show".
Local entertainment journalist Eddie Rowley tweeted that a publicist said McGraw was treated on site and will be fine. Hill, Little Big Town and Kacey Musgraves were among performers at the Glasgow concert.
Hill and McGraw are scheduled to begin their 29-city Soul2Soul tour in the United States in May.
On 3 March, he praised the USA sporting goods store Dick's, after it raised the minimum age for anyone buying guns or ammunition to 21 years. "A true hero who lost his life protecting the children", McGraw tweered.
Faith then appeared to struggle to come up with another song to close out the show, and after fielding a few audience requests (all Tim's songs), she finally asked, "Do you guys like gospel music", then sang a few lines of "What A Friend We Have In Jesus", before ending the show.