England's injury problems continue to mount as head coach Eddie Jones finalises his first Elite Player Squad in preparation for the RBS 6 Nations.
Hooker Dylan Hartley, second row George Kruis, wing Jack Nowell and number eight Ben Morgan have been added to a lengthy injury list that sees seven players miss all or part of the Championship.
The latest round of Aviva Premiership action was not without reason to cheer, however, as Manu Tuilagi returned from a long-term groin injury and will come into contention for the 33-man squad to be announced at Twickenham on Wednesday.
Potentially Jones' greatest concern is the latest setback endured by Hartley, the Northampton hooker who was the front-runner to replace Chris Robshaw as captain.
Hartley's comeback against London Irish on Boxing Day ended a seven-week spell out with concussion, but since his return he has been only second choice behind Mike Haywood at Saints.
Jones was present at Welford Road on Saturday as Leicester emerged 30-27 winners in the midlands derby, but a rib problem saw Hartley removed from the bench shortly before kick-off.
Meanwhile his two closest rivals to be England's hooker - Tigers' Tom Youngs and Jamie George of Saracens - were able press their claims in a pair of exhilarating showdowns between title rivals.
"Dylan trained a little bit in the week but at the last minute he was just too sore to play," Northampton director of rugby Jim Mallinder said.
"It's a bang to the ribs, and he has done some training this week, so he is not going to be out for a long time."
If Jones decides Hartley's lack of game time rules him out of contention - he has made just one start and one substitute appearance in two months - then it is hard to see who he turns to for the captaincy beyond incumbent Chris Robshaw.
Robshaw was outstanding in Harlequins' 29-23 victory over Saracens and is making a compelling case for his selection at blindside flanker for the Six Nations opener against Scotland on February 6.
"Chris has recuperated after the World Cup and is mentally really fresh," Quins director of rugby Conor O'Shea said.
"Everyone is talking about everyone else apart from the man who is an unbelievable rugby player. Chris was incredible again against Saracens."
While Robshaw was rampaging around Twickenham Stoop with England forwards coach Steve Borthwick watching from the stands, Kruis lamented the end of his afternoon after just 90 seconds.
The 25-year-old was knocked out by a swinging arm from James Horwill and must follow the return to play protocols for concussion ahead of Saracens' Champions Cup clash with Ulster on Saturday.
Exeter's 19-10 home victory over Gloucester produced two further doubts with Nowell and Morgan failing to last the afternoon with respective knee and shoulder injuries.
They will be assessed early in the week amid initial uncertainty over the severity of the damage sustained at Sandy Park.
The latest concerns come with locks Ed Slater and Dave Attwood, props Kieran Brookes and Alex Corbisiero, back row Dave Ewers, wing Jonny May and centre Henry Slade already missing varying lengths of the Six Nations.
Jones must decide whether to include Tuilagi in the EPS following his comeback as a 52nd-minute replacement at Welford Road after 15 months out.
The wrecking-ball centre was a late adjustment to Leicester's bench and director of rugby Richard Cockerill insists he must be given a run of games before being considered by England.
"I will speak to Eddie in the next few days. Manu will keep improving, but the start of the Six Nations is unrealistic because we need to make sure he is 100 per cent right," Cockerill said.
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