Skipper Scott Brown and defender Mikael Lustig will be missing again for Celtic's SPL clash against Motherwell at Fir Park on Wednesday night.
Brown has seen a specialist about his abductor problem and will discover on Monday if he requires surgery while Lustig is out with a thigh injury.
Defender Charlie Mulgrew is a doubt with a glute problem.
Motherwell will be without defender Fraser Kerr after he missed the weekend defeat to Ross County through illness and remains out of action.
Fellow defender Zaine Francis-Angol is a doubt after being forced out of Saturday's match.
Midfielder Tom Hateley and defender Steven Hammell both missed the clash with the Highlanders and McCall hopes one of them could be passed fit for the visit of the Hoops.
The Teessiders face Rafael Benitez's men in their delayed fifth-round tie at the Riverside on Wednesday evening hoping to claim another Barclays Premier League scalp after dumping neighbours Sunderland out of the fourth round of the Capital One Cup.
However, Mowbray is acutely aware of the threat posed by the Blues even if Benitez chooses to shuffle his pack, and has told his side only hard graft will give them a chance of containing them.
He said: "When you haven't got world-class players, you have to first and foremost have a work ethic. You have to try to condense space, you have to try not to be isolated one-on-one in certain areas of the pitch.
"And yet, you have to balance that off with having an attacking threat. You have to have a way of trying to score a goal and if you have everybody back, it's very unlikely you are going to have too many attempts. That's the balance for any manager.
"Watching Manchester City at the weekend, it was 'You have an attack, we have an attack and see how can hurt the opposition the most'.
"I would have to say, we won't be playing like that because I doubt we are going to leave three up front and wait for our defence to give it back to them and we attack them and they all run back.
"That's the difference. Athletically, we have to cover more ground than they do. They can rely more on their technique and their talent to pick the right pass."
Boro will head into the game having won only one of their last nine npower Championship fixtures, a run which has seen them slip out of the play-off places.
But it is Mowbray's opposite number Benitez who will head into the contest knowing failure will pile the pressure on to him with his detractors becoming increasingly vociferous.
However, the Boro manager is wary of the strength which can emerge from adversity and believes the Spaniard's track record proves he can handle the heat.
He said: "In adversity, the group of players should be feeding off that and becoming stronger and more unified, and I am sure that's happening at that club.
"The decision for Rafa to take that job was made because he is a top manager who has won European trophies, who has won leagues in just about every country he has been to.
"He is a good football man. I don't know him well, but I have been in his company and he loves to talk football tactics.
"I have only got respect for Rafa Benitez. It is a tough job, of course, but he seems very professional, long in the tooth regarding his job from the point of view of getting on with his job and trying to win trophies for the club.
"Every football manager at times feels the wrath of the support and you have to be very, very single-minded to sit in a football manager's job in 2013 because of the social media aspect of the world now, everybody can do your job, everybody has got an opinion.
"You have to be single-minded and I think Rafa is showing everybody he is pretty single-minded, getting on with his job, trying to win games."
The south Wales outfit have seen days like this before, notably following their promotion to the Premier League in May 2011, but the added edge of securing a first piece of major silverware in the club's centenary season ensured a massive presence along the 1.2-mile route.
Even the cold and overcast weather conditions could not put a dampener on the occasion as fans crammed along the city's streets to acclaim the players, management and staff.
The open-top bus carrying the players set off from the Dragon Hotel before making its way down the city's Kingsway and heading down to St Helen's Road to the Guildhall for a civic reception.
It seemed apt that part of the route took the current squad within sight of where the Swans' former Vetch Field home once stood, for it was almost 10 years ago at that very venue that this fairytale story began.
A 4-2 victory over Hull, courtesy of a hat-trick from striker James Thomas, now an ambulance driver, ensured Swansea retained their Football League status.
Current squad member Leon Britton was the sole survivor from the side who beat the drop to feature at Wembley.
Club captain Garry Monk, who stood at the front of the bus holding aloft the trophy with vice captain Ashley Williams, is another who can recall the club's days in the fourth tier.
Back then, manager Brian Flynn would hold training at any available space: a local astroturf, a free playing field, or even on the beach.
There are question marks over how long the likes of Laudrup and inspirational top scorer Michu may remain with Swansea, but there were few among the cheering throngs who were too concerned by such thoughts.
Instead they will dream of forays into Europe as part of the Europa League spot secured by Wembley glory, and wonder what will happen in the next chapter of this most remarkable of sporting stories.
The Tangerines head north knowing a win would take them to within just a point of Terry Butcher's Caley Thistle in their quest to climb the table as they look to finish the season with a flurry.
McNamara watched his side concede two goals in last Sunday's 2-2 SPL draw with Hibernian at Tannadice, a game in which United required a late penalty from Johnny Russell to earn a share of the spoils.
And McNamara does not want to see a repeat of any slack defending when they head to the Highlands for their important SPL clash.
McNamara said: "Hopefully we have learned our lesson from that point of view.
"It's something we have to work on and have got to do better.
"Inverness have been playing well this season and thoroughly deserve to be where they are in the league, which is second top.
"They score a lot of goals so obviously we want to keep things tight at the back and not help them in any way.
"We were annoyed at the goals which we lost against Hibs but that's in the past and we have to try and improve on that."
McNamara takes his side to the Highlands to face Euro-chasing Inverness and knows they will have to be firing on all cylinders if they are to return to Tayside with all three points.
He said: "We know it will be nothing other than a difficult game.
"It will be a test for the lads and we have to start the game better than we did against Hibs when we were slow to get going.
"Having watched Inverness, it's clear they have had good legs and can get about the park so they are dangerous opponents.
"But we have to focus on our own strengths and hopefully take the game to them.
"The league is so tight that a few wins can make a big difference which is what we're aiming for."
United have signed Swedish defender Marcus Tornstrand but the 23-year-old free agent will not feature at Inverness as he works to build up his match fitness.
Gavin Gunning is sidelined following a knee operation but McNamara has no fresh injury worries.
The Hoops have garnered 62 points after 28 games and, 21 clear of Inverness at the top of the table, are striding unchallenged towards retaining their title.
Ahead of the trip to Motherwell on Wednesday night, the Parkhead manager pointed to several reasons why his side should be motivated to carry on from their 5-0 drubbing of Dundee at the weekend.
"We want to win our remaining 10 games and finish the season strongly," said the former Celtic captain.
"I think the points total is important, we had 92 and 93 in the last two seasons so we would like to get up around 90 again and we still have a bit of work to do to make that target.
"I want these young players to keep progressing and try and adapt to any environment or challenge that is put in front of them.
"We have scored 100 goals already this season so can we get close to 100 league goals? Can we get 90-plus points, can Gary Hooper get 30-plus goals, can Fraser Forster keep clean sheets, can the midfield pitch in with more goals? There is so much still to play for.
"It's a great time to be involved with Celtic.
"I look at my time and I look at these players now. They are playing in the last 16 of the Champions League and they are going for their second title.
"There may be players who won't be here next year for one reason or another so they should enjoy this time."
Lennon insists the next week will define the club's season.
The champions face St Mirren in the quarter-finals of the William Hill Scottish Cup on Saturday looking to avenge the Scottish Communities League Cup semi-final defeat to the Buddies.
After that Celtic travel to Turin for the second leg of their Champions League last-16 clash with Juventus on Wednesday night, hoping against hope to recover a 3-0 deficit from the first game at Parkhead.
"Obviously we have places up for grabs for the Scottish Cup and Champions League so there has been no sign of anyone taking their foot off the pedal," Lennon said.
"The squad is vibrant and healthy and I will use it but obviously I am mindful of the fact that Motherwell is a big game, St Mirren is a huge game for us and obviously Juventus as well.
"These are three games that will shape the season one way or the other and I will go strong in all of them."
Lennon will disregard the interest surrounding James McFadden, who rejoined Motherwell last week - although the Fir Park side have lost both games in which he came on as substitute, at home to Dundee United and away to Ross County.
The Northern Irishman, who had talks with the former Everton and Birmingham forward in October 2011 before a potential move fell through, said: "I am aware that James has gone back there and I know he hasn't played a lot of football so I don't know how far down the road he is with his conditioning.
"But I assume that he will feature at some part, if not start the game.
"We did have talks with himself and representatives but he chose to go elsewhere.
"The only problem James has had is with injuries, stopping him from being the talent that we all thought he was going to be.
"Hopefully he can get an injury-free run and get back to the form he showed four or five years ago.
"I am not sure he has much to do with (Motherwell's two defeats), I think he has played only in fits and starts after being out of the game so long, which you would expect.
"It is a bit like Kris Boyd (signing for Kilmarnock), it is a signing that has captured people's imagination.
"But it is no distraction for us, we have our own priorities and we want to win the game and keep momentum going."
Brown's controversial appointment following the departure of Barry Smith last week has not gone down too well with many of the Dark Blue faithful who are facing the prospect of returning to Irn-Bru First Division next season as they trail St Mirren by 15 points at the bottom of the table.
The former Dundee and Rangers player has shrugged off the negative reaction to his return to the club but knows the focus will be on him in his first game in the dugout, after watching his new charges lose 5-0 to Celtic at Parkhead from the stand.
Saints boss Lomas, though, is looking for his team, fresh from a 1-0 win over St Mirren at the weekend, to keep pressure on second-placed Inverness, whom they trail by just one point.
"We have got to be professional, prepare ourselves right and stick to our game plan," he said.
"We know that Dundee will probably get a lift, teams normally do in those circumstances.
"When a new manager takes over you normally see that in his first game.
"I don't know John Brown but I watched him as a player and he was a very good player, very under-rated and he has great enthusiasm.
"But we can only concentrate on ourselves and what we do."
Lomas does not discount the possibility of Dundee escaping the drop.
"It is possible," he said.
"They still have enough points to play for and they are playing for places in the Scottish Cup quarter-finals, so there is a lot to play for.
"I have watched them in the last two or three months and they have been unlucky in certain games.
"There wasn't much in it when we played them and Hibs were very lucky to beat them at their place.
"They have improved as the season has gone on and they seem to be a lot tighter at the back, so we have to do our jobs.
"We are in a good place, coming off a hard-fought win and it will be the same on Wednesday, it will be another battle."
While Murray Davidson is suspended, fellow midfielder Chris Millar has recovered from a groin injury and skipper Dave Mackay is over an ankle injury and is set to come back in after being on the bench against St Mirren.
The former West Ham and Manchester City midfielder said: "It is good to have the two players back.
"Dave is our captain and he is a seven out of 10 at the very least every week, and often better.
"Chris provides energy in midfield and can play in a few positions so he has been a miss as well.
"So I have a selection dilemma which is nice."