Ulster winger Jacob Stockdale has been ruled out for six to eight weeks with a grade 2 hamstring strain sustained in training last week.
The 22-year-old was unlikely to feature in the first few of Pro14 games after playing a significant part of Ireland's June Tests against Australia.
Stockdale's injury is another blow to Ulster who will start the season without the likes of fellow backs Louis Ludik, Luke Marshall and David Busby will also miss the early part of the season with injuries.
Ludik faces several months on the sidelines after picking up an injury on the final day of last season, while Busby and Marshall are recovering from torn ACL injuries. Centre Marshall tore his ACL in his right knee in the Pro14 play-off against Ospreys for a place in the Champions Cup in May and is not expected to feature until the new year.
Stockdale scored 20 tries for Ulster and Ireland last season, setting a new Six Nations record with seven touchdowns in five games. Andrew Trimble and Tommy Bowe retired at the end of last season while Charles Piutau departed to play in the English Premiership with Bristol.
The short-term signing of Henry Speight will assist the side with his ability to play full-back and wing and will join the side in training this week after arriving from the Brumbies. He will return to Australia on 31 December ahead of the 2019 Super Rugby season.