Team Sky rider Jonathan Tiernan-Locke has reportedly been given more time by world cycling’s governing body, the UCI, to explain apparent discrepancies in his blood values.

Last month, Team Sky confirmed newspaper reports that the 28-year-old from Devon had been asked to account for differences in his blood values from samples taken in late 2012 and those recorded after his move to Sky for 2013.

Telegraph.co.uk reports that the UCI says it has power to extend the 20-day period, which expires this week, that Tiernan-Locke has to respond to the letter it sent him in late September asking him to explain the differences in the values.

The UCI, which is said to have been in regular contact with Team Sky over the issue, added that it will use its discretion in this specific case if it is asked to do so. The granting of such an extension is not believed to be unusual in such a case.

Tiernan-Locke, who became subject to regular blood testing after his overall victory in the 2012 Tour of Britain, was an Endura Racing rider during the period that is the subject of concern.

However, Endura, the clothing brand that owned and sponsored the team, said in a statement last month that he spent much of the 2012 season training under Sky’s supervision ahead of his eventual move.

Both Sky and Endura have highlighted that the discrepancies in Tiernan-Locke’s blood values may be due to issues such as illness or fatigue, besides doping.

The rider, who had a lacklustre debut season with Sky, has reportedly had problems adapting to the demands of training and racing at WorldTour level. He has also struggled with illness and tiredness this year.

Tiernan-Locke, who spent several years out of the sport in his early twenties as he fought a debilitating virus and focused on his studies, came to the attention of WorldTour teams in early 2012 after victories in two early season French races.

His sudden emergence onto the continental scene through those victories, in the Tour Méditerranéen and Tour du Haut Var, led to French sports daily L’Equipe posing the question: “Are we in the presence of a champion or a chimera? Tiernan-Locke can only be one or the other to win five races in a row.

“He’s part of a team from the third division, a category where the riders don’t have to submit to biological monitoring, via the blood passport programme of the Union Cycliste Internationale.”

The rider, and those close to him such as former team manager at Endura Brian Smith, have strenuously denied claims that his performances might have been artificially enhanced.

Once Tiernan-Locke submits his explanation to the UCI, it will be examined by the same three-person committee that identified the concerns in the first place.

If the committee decides the explanation warrants further examination, the matter will be referred to an 11-member committee of experts, who will decide whether disciplinary action is needed.