Ulster Rugby have been plunged into a second row injury crisis that threatens to seriously test and stretch their resources for the critical final group matches in the New Year that will settle quarter-final qualification.
The 1999 European champions already had inspirational captain Johann Muller and Lewis Stevenson (knee) on a lengthy injury list and now Dan Tuohy is in danger of being sidelined for the contests against Glasgow Warriors and Castres Olympique.
Irish international Tuohy damaged his calf in the 10-9 Round 4 defeat to Northampton Saints at Ravenhill - Ulster's first loss in 14 matches this season - with scans ruling him out of action for a month.
Tuohy had been in impressive form this season, helping Ulster to the top of the PRO12 and to the brink of the Heineken Cup knock-out stages with his last-gasp try at Franklin's Gardens earning the Irish club an impressive bonus point on the road.
Meanwhile Muller is expected to be ruled out for a further six weeks after suffering a broken arm in the Round 3 win over the Saints at Franklin's Gardens.
The X-ray revealed that the Springbok star suffered an undisplaced fracture of his radius and he underwent surgery last week - having only recently returned to action after being ruled out for almost six weeks by a thumb injury.
It leaves Ulster with Iain Henderson and Neil McComb as their recognised locks and back-up coming from Robbie Diack.
