The mystery 'medical issue' keeping Western Bulldogs ruckman Tim English out of contact training has been revealed.

English hadn't been participating in the Bulldogs' recent contact sessions this pre-season due to an undisclosed ailment, with the precise cause previously unknown.

However, on Monday, the Western Bulldogs confirmed the 26-year-old has been managing migraine-related symptoms.

Despite speculation English was battling concussion, Monday's clarification provided context to the ruckman's extended stint on the sidelines.

After undergoing assessments over the New Year period, English will return to Bulldogs training next week.

According to specialists, "Tim's symptoms were not related to concussion and [were] more consistent with a migraine".

Understandably, the Bulldogs took a cautionary approach with their prolific ruckman, who is slated for restricted free agency at the end of this year.

Tim English during the 2022 AFL Round 1 match between Melbourne and Western Bulldogs (Photo by Cameron Grimes / Zero Digital Media)

After a stellar season last year that saw English earn his maiden All-Australian blazer, the Bulldogs will be desperate to retain the West Australian's services.

The towering ruck-forward has been consistently linked with a move back to his home state, however, the Dogs are expected to do everything in their power to convince him to remain at the Kennel long-term.

The Bulldogs, hopefully with English in tow, are scheduled to play two pre-season games against Hawthorn, with the first matchup to come in late February.