Concern over concussed Kruis
The England pair of Jack Nowell and George Kruis were both injured.
Exeter wing Nowell twisted his knee against Gloucester, while Saracens lock Kruis was concussed against Harlequins and taken off on a stretcher.
Saracens crashed to their first defeat of the season as Harlequins battled to a 29-23 victory over the English Premiership leaders in a stormy clash at Twickenham Stoop on Saturday.
After a 15-match unbeaten run left them as the only unbeaten team in Europe this season, the reigning Premiership champions were finally beaten to leave them just three points clear at the top and to make matters worse they also departed with fitness concerns over George Kruis.
Kruis was struck with a swinging arm by James Horwill just 90 seconds into the match and play was delayed by eight minutes as the England lock carried off on a stretcher.
Horwill shook his head in disbelief when shown a yellow card by referee Craig Maxwell-Keys, but for the remainder of the tempestuous derby the former Australia captain was magnificent and his reward came with the decisive 80th-minute try.
Saracens' task was made harder when Rhys Gill was sent off in the 65th minute for his role in a spear tackle on centre George Lowe.
Gill was assisted by Petrus du Plessis as Lowe was picked up and dropped on his head, but it was the replacement hooker who was shown a red yard by Maxwell-Keys, who initially brandished a yellow before changing his mind after seeing a replay of the incident.
Elsewhere, England centre Manu Tuilagi made a long-awaited comeback from injury as Leicester claimed a dramatic last-kick 30-27 victory over Northampton at Welford Road.
The new England coach, Jones, looked on as Tigers star Tuilagi, who had been sidelined for 15 months due to a serious groin problem, came on as a 52nd minute substitute before Freddie Burns' stoppage-time penalty saw Leicester home.
Tuilagi proved a late inclusion on the Leicester bench and he must now wait to see if he makes Jones' first elite player squad, which will be unveiled next Wednesday, 24 days before England's Six Nations opener against Scotland at Murrayfield.
Saracens Director of Rugby Mark McCall admitted his below-par side were not worthy of victory at the Stoop.
The boot of Ben Botica finally condemned 14-man Saracens to their first defeat of the season, as Harlequins ran out 29-23 winners after a sensational contest at the weekend.
The visitors stay top of the Premiership despite the loss, but both Quins and Exeter Chiefs closed the gap at the top of the table with their victories, and McCall is calling on his side to show some resolve after their first setback of the season.
"I thought our set-piece dominated the first 20 minutes or so, but we gave away an unbelievably soft try," McCall said.
"That was just a switch off moment by one person in the line-out that went on for five points.
"But just in general I don't think we deserved to win.
"I think our discipline was not good enough and I think they won the scraps.
"They were really up for it and with all those fifty-fifty battles which we are pretty good at usually, we weren't so good at.
"So it's disappointing to lose because for those reasons but we have to move on.
"This group in the past has shown it is pretty good at dealing with the odd set back here and there.
"We have a pretty big game to get our teeth into against Ulster and we can't feel sorry ourselves, get stuck into the week and that's all."
* Meanwhile Conor O'Shea is relishing the determination his side are showing at the moment after the gritty comeback.
The hosts, who are now unbeaten in four league matches, somehow found themselves ahead at the interval when Rob Buchanan and Jack Clifford cancelled out Neil de Kock and Billy Vunipola's efforts, despite Sarries dominating the opening stages.
Owen Farrell put the visitors back into the lead from the tee, but after replacement Rhys Gill saw red for a dangerous tackle on George Lowe the tables were turned and three Ben Botica penalties and James Horwill's late try clinched a 29-23 win.
It was a first defeat in 15 games for Saracens and only Quins' second victory in their last 15 matches against the league leaders, and O'Shea put it down to a battling performance.
"What a game of rugby that was," he said. "It's what the Aviva Premiership Rugby is all about; the Stoop was rocking.
"It's only game nine but I just love the bite that was out there tonight. We said we wanted to be physical, but we were also enterprising.
"Obviously the huge turning point in terms of giving us the absolute foothold was Rhys' sending off, but don't think you can argue with that.
"I'm thankful that George Lowe wasn't injured because we all know what he has gone through the last two to three years, but otherwise it was a great game of rugby between two teams who will be fighting hopefully towards the end of the year.
"Hopefully it gives Nick Easter a little lift because he's had some personal problems of late, and he sent out a text saying we could win before the game, which means a lot to the players."
