David Millar’s 14-year love affair with the Tour de France looks to have ended prematurely and painfully after his Garmin-Sharp squad withdrew him from their Tour selection after expressing doubts about his form.

The Scot, who will retire from cycling at the end of the season, was all set to start the Tour for the 13th time in his career in support of his leader Andrew Talansky. Garmin had expected the 37-year-old Millar to perform at the weekend’s national championship road race in spite of a lingering chest issue but, after he did not complete the race, Millar was informed on Monday morning that he would not be riding the Tour.

“I’m devastated that the team don’t trust me to the job as I’ve always done,” an audibly upset Millar told the Guardian. “I’m in shock. I don’t understand why I’m not selected. The bottom line is that I was selected when they chose the team a week ago and they pulled me because they were worried about my health; that is counterintuitive because they wanted me to race the nationals to prove I was healthy.”

In the small hours of Monday morning, Millar filed a prescient tweet on his Twitter feed @millarmind: “None of my team will answer the phone to me. I under-performed at the nationals. I’m now so scared about losing my Tour spot I can’t sleep.”

None of my team will answer the phone to me. I under-performed at the nationals. I'm now so scared about losing my Tour spot I can't sleep. — David Millar (@millarmind) June 30, 2014

Millar pulled out of Thursday’s British time trial championship at half-distance due to his cough, which had improved by the weekend, however. In Sunday’s road race championship, he missed the decisive 10-man move, but figured in the chasing group until he pulled out at 42km to go. “No matter what the situation I’ve always finished the Tour and done my job considerably better than others,” he said. “In 2010 I got through with two broken ribs.”

Coming as it does after Sir Bradley Wiggins’s non-selection for Sky’s squad for the Tour, Millar being dropped by Garmin will also be a disappointment to British fans and to the Tour de France organisers at the start in Yorkshire. Peter Kennaugh is another who feels he has been left on the sidelines unjustly after being left out by Sky. That leaves the Kenyan-born Chris Froome, Geraint Thomas and Mark Cavendish as definite British starters, with Alex Dowsett named in Movistar’s pre-selection but yet to be confirmed.

Millar’s Tour career began in 2000 with a bang when he won the opening time trial at Futuroscope with a ride that shocked the cycling world and made him only the fourth Briton to wear the coveted leader’s yellow jersey. In 2002 he added a second stage win at Béziers, and a year later he outperformed Jan Ullrich and Lance Armstrong to claim a time trial victory at Nantes.

Less than a year later, however, just before the 2004 Tour started, he was arrested by drugs police and he confessed to using the blood booster erythropoietin; the 2003 stage win has now been removed from the record at his own request as he had been doping in the buildup to that Tour.

Millar returned to the Tour immediately after his suspension ended in July 2006, reborn as an anti-doping campaigner, and completed the race with no competitive miles in his legs; he has finished the Tour every year since then. In 2011 he was part of the Garmin squad that won the team time trial stage, while in 2012 he added another road race stage win by outsprinting France’s Jean-Christophe Peraud in Annonay.

Millar now expects to defend his time trial title in the Commonwealth Games for Scotland and is scheduled to end his career this September with the Vuelta a España and possibly the world road race championships.