"We've got a couple of niggles, so we're just monitoring those at the moment," McCullum told Sky Sports. "Every team that goes into a series has got a couple of little things that you need to work through, but we're pretty confident we'll have a good squad to be able to pick from.
"For the first Ashes Test, I think [Anderson and Robinson] should be fit. They won't be fit for this one against Ireland. We'll just have to monitor it over this next sort of while, but we've got some great options right throughout the squad.
"Stokesy is progressing well too," he added. "He looks really fit as well, looks in great order and has a big smile on his face. He is delighted to be back around the group and as our leader, having that sort of energy he brings is fantastic, so again we'll monitor that and see what happens.
"I think he'll bowl at some stage throughout the summer, yeah, no doubt. He is a world-class allrounder and if he is able to bowl, fantastic. If not, we'll find a way.
"Who knows if we are going to win this summer but we're going to go into it with the right attitude, the right environment, and the right team which believes it's got a chance"
Brendon McCullum
"When I first took over this job, people said there weren't much depth in English cricket and I disagree with that completely," McCullum added. "I think there is an immense amount of depth. There's no point being concerned. You just deal with what you've got and play the cards you are handed. I am confident we will have a good squad to pick from right throughout the summer, and we'll see how we go."
England come into the season with their reputation transformed in the 12 months since McCullum and Stokes took over in a new coach/captain partnership. They have won ten of their 12 Tests in that period, while their most recent outing was an extraordinary one-run loss against New Zealand in Wellington in February, a result that reinforced the "no-fear" brand of cricket that the team has embraced in the interim.
And though the immediate challenge will be to overcome an Ireland team that rolled England aside for 85 in their last appearance at Lord's in 2019, McCullum acknowledged that the Ashes is already looming large in the team's thoughts.
"It's been a great year, this will be a big summer," McCullum said. "There will be a lot of eyeballs on us, not just in the UK but also around the world, and that's what you want to be involved in. Who knows if we are going to win this summer but we're going to go into it with the right attitude, the right environment, and the right team which believes it's got a chance.
"We're a team that knows how we want to play now, and we're not afraid to lose, which is quite a remarkable trait, and that's led by the skipper and some of the senior players as well. If we do play how we want to play, we give ourselves the best opportunity and we've got the talent to put world-class teams under pressure."
As for whether England will be able to play their new liberated brand of cricket against a team of Australia's talent, and in the full glare of an Ashes summer, McCullum was phlegmatic about the qualities within the team set-up.
"Look, Australia is a very good line-up, right? They have world-class bowlers and have been a very good team for a long period of time. They'll be a formidable challenge for us, but it is a challenge we're really looking forward to," he said. "It is what you want to play sport for, right? You want to be playing against the best, in the biggest series and on the biggest stage, and there is no greater opportunity than what lies in front of us in the next six to eight weeks.
"From our point of view, we don't go in to it prescribed with our method, it is about trying to ensure we are nice and free of mind, and being able to live in the present and deal with what comes our way. If it is a high-scoring rate, great. If it's not, that's great too. We'll just see what happens."
Andrew Miller is UK editor of ESPNcricinfo. @miller_cricket