Ireland's record points scorer David Humphreys will miss Ulster's pre-season opener against London Irish next Friday due to a calf strain.
The 33-year-old is to sit out the Ravenhill friendly as a "precaution", while Wallaby prop Rod Moore (knee) and Ireland Sevens flyer Andrew Maxwell (ankle), both recovering from minor surgery on their injuries, are also sidelined for the clash with the Exiles.
New signings Justin Fitzpatrick and Justin Harrison are both expected to make the province's starting line-up, which is confirmed on Tuesday.
Currently overseeing a week-long training stint at St Andrew's in Scotland, Ulster coach Mark McCall confirmed: "David's absence is just a precaution while both Rod and Andy are well on the road to recovery.
"Training has been good with no serious injuries, just the usual bumps and bruises.
"It's has been particularly beneficial for the new boys coming in, especially Justin Harrison who has settled in really well," McCall told BBC Sport.