On the same day that the Australian rider announced his two-year signing with Trek-Segafredo, his current team BMC confirmed that he would require rest and recovery ahead of the Spanish Grand Tour start.
Explaining the situation on Thursday, BMC's doctor Dr. Daniele Zaccaria said: "Richie Porte woke up with some gastrointestinal issues this morning."
"We have been monitoring him during the day, and although it is nothing too serious we feel the best thing for his recovery is to rest for the remainder of the day, which will mean missing the race press conference this afternoon and team presentation."
The team doctor added: "Riche should be able to do a light training session tomorrow [Friday] and we expect him to be on the start line on Saturday.
"Although this is not ideal two days before the start of the Vuelta a Espana, we are confident that adequate rest will help Richie to get back to his pre-race form."
The Vuelta a España represents a second chance for the 33-year-old, who crashed out of the Tour de France on stage nine.
The general classification contender sustained a broken collarbone in France, and Saturday's time trial in Malaga will mark his return to competition in what he has referred to as the "last chance saloon" to pull back a GC result this year.
His last outing at the Vuelta was in 2012, when Porte said he received an "absolute kicking" - and he intends to assess his form as the race goes on.
Cycling Weekly's Tech Editor Michelle Arthurs-Brennan is a traditional journalist by trade, having begun her career working for a local newspaper before spending a few years at Evans Cycles, then combining the two with a career in cycling journalism.
When not typing or testing, Michelle is a road racer who also enjoys track riding and the occasional time trial, though dabbles in off-road riding too (either on a mountain bike, or a 'gravel bike'). She is passionate about supporting grassroots women's racing and founded the women's road race team 1904rt.
Favourite bikes include a custom carbon Werking road bike as well as the Specialized Tarmac SL6.