Boro made an early breakthrough with the signing of Joe Lumley at the start of what is likely to be a busy summer.
Neil Warnock says he wants eight or nine new signings, not to completely revamp his starting XI but to add some much-needed depth.
After the arrival of Lumley, attention will switch to the other end of the pitch, with the front-line the priority.
We assess each area of Boro's squad, the options, who could go, what might be needed and how the side could line-up next term.
Goalkeeper
An important piece of the summer jigsaw was the capture of a goalkeeper - probably two - so getting Joe Lumley in was a big early boost.
Lumley has Championship experience and arrives hungry to take his chance as No.1 after losing the gloves at QPR this season. He doesn't lack ambition - revealing his hopes to play in the Premier League and for England one day.
A keeper can't be judged on one cameo and he was in Boro's thoughts long before Rangers visited the Riverside in April, but he was excellent that day. To make those pointblank saves in any circumstances is impressive, to do it coming in from the cold after watching on from the bench and not expecting to have to pull on the gloves is outstanding.
Warnock sees Lumley as his No.1, but still needs a deputy. The young keepers on the club's books are well thought of but need to be playing, so in an ideal world will go out on loan. An experienced reserve keeper - in the mould of Jordan Archer - would tick a box. Will it be Archer? The retained list is imminent and will tell us more, but it depends on what else is out there, how impressed Warnock was with the former Millwall keeper and if he has any other offers.
Watch this space.
Defence
Warnock won't be losing any sleep this summer over his defence. In fact, as he's talked about on a couple of occasions recently, the Boro boss believes his first choice back four or five is as good as any backline in the Championship and would be able to hold its own in the Premier League.
So don't expect any major changes with the defence this summer. At centre-half, Warnock has Dael Fry, Grant Hall, Paddy McNair (if he wants to play him there) and Anfernee Dijksteel (if he's playing a back three). There's also Nathan Wood to consider. Wood is an interesting one. There's no doubt he has a massive future and Warnock rates him highly. It's whether the boss thinks he'll play much football for Boro next term. If he doesn't, he won't want the 18-year-old spending the bulk of the campaign on the bench. He'd much rather he was benefiting from regular football elsewhere. If that was the case, there'd be one almighty League One scrap for his signature.
If Wood is allowed out on loan and if Warnock thinks he might use McNair in midfield more often next season, then a centre-half is needed, especially when you consider how much the boss has talked about the importance of depth. We know how much he values Fry, Hall, McNair and Dijksteel, but what if Dijksteel is playing at full-back in a four and Fry is injured? Suddenly he'd be left short. So although Warnock is more than happy with his defence on the whole, it wouldn't be a surprise to see one centre-half come in.
Warnock has been very impressed with Jack Robinson but a loan would benefit the young defender.
At full-back, Warnock has options on the right, with Dijksteel, Darnell Fisher and Djed Spence, though the boss might have a decision to make on the latter if keen clubs firm up their interest with a bid. Spence hasn't kicked on and was poor this season. A parting of ways - only if the price is right for a young player with plenty of potential - might suit both parties.
On the left, Marc Bola will continue as first choice but what about cover? Marvin Johnson's situation is uncertain as things stand and Warnock clearly doesn't see Hayden Coulson as a defender.
Midfield
Warnock wants consistency and reliability and he's got that in his midfield. Jonny Howson was one of the first names on the teamsheet this season and that will continue to be the case next term. Even when Britt Assombalonga had the armband, Howson was the leader.
Sam Morsy endured a bit of a frustrating in and out first season at the club but there was more than enough evidence of why Warnock wanted him. He provides the tenacity and bite Boro really lacked at times, but is a fine player and runner as well.
It was probably George Saville's best season for Boro. It was definitely Marcus Tavernier's best season at Boro.
And there's Paddy McNair to possibly consider as well. Earlier in the season Warnock was adamant McNair was definitely a defender, but the Northern Ireland international impressed in a more advanced role late in the campaign. Food for thought.
Get the latest Boro & transfer news delivered to your inbox
It's a busy spell on and off the pitch.
The Championship campaign is underway, while off the pitch Boro continue to work tirelessly on adding to their squad.
You can keep up to speed with any developments and get the latest transfer news in your inbox by signing up to our free newsletter.
Your daily helping will include breaking transfer stories and analysis, as well as in-depth features and coverage of every game and Neil Warnock press conference.
To sign up to the newsletter, all you need to do is pop your email address in the box at the top of this story and click 'subscribe'.
For more details, please CLICK HERE.
Lewis Wing impressed at Rotherham. Warnock won't make any snap decisions and will give Wing ample time to impress in pre-season, but the 25-year-old looks to have a job on his hands to force his way back into being a regular. Though, as Warnock has talked about a lot of late, there's always one player who surprises him in the summer and forces a change of plan.
How will the midfield line-up next season? Warnock likes the idea of playing either a 4-3-3 or a 5-2-3. If it's the latter, you could imagine a steely two of Howson and Morsy, with Tavernier as one of the forwards playing off the striker.
Connor Malley took his chance at the end of the season and will get further opportunities in the summer before a decision is made on whether or not he should go out on loan. A loan is likely for Hayden Hackney.
In Warnock's eyes there's no need for major surgery in the defence or midfield. But it's a different story in the forward line....
Attacking midfield/wingers
Right. The attack. That's the direction in which most of Warnock's transfer focus will be aimed.
We know his priority is up-front, where he's looking for three new strikers. But the flanks and/or the attacking midfield areas also need work this summer.
Yannick Bolasie and Neeskens Kebano have obviously come to the end of their loan deals at the club and both are unlikely to return.
Marvin Johnson and Nathaniel Mendez-Laing are also out of contract.
That would leave Marcus Browne and Hayden Coulson as the only senior wide players on the club's books, though when the latter was handed an opportunity at the end of the season it came in a No.10 role. There's Marcus Tavernier to consider as well, but Warnock likes him more central pulling the strings. And obviously Duncan Watmore, who, after a hugely impressive first season, could further flourish playing off the right striker. Warnock loved the way Watmore got his head down and did a job for him in several roles late in the season, but knows the former Sunderland man will be best as a No.10 buzzing around and working off a striker. The energetic Tavernier and Watmore playing off a striker would be tiring to watch, never mind play against.
Warnock has talked about wanting versatile wingers who can play on both flanks and potentially be used central as well, as we saw with Browne before he suffered the serious knee injury. Kadeem Harris and Junior Hoilett are two players who Warnock knows well, are available on a free and have been linked.
Chances need making for the strikers who arrive. Creativity is key this summer if Boro are to send their goals scored column soaring north. It should help that the strikers and attacking midfielders/wingers are arriving in the same summer. Warnock knows how he wants Boro to play so isn't necessarily targeting individuals but forwards who will fit together. With the 5-2-3 for example, the plan would be to have two tricky, energetic and forwards playing off one powerful and physical striker who brings them into play, just like he did at Cardiff when Mendez-Laing and Hoilett played off Kenneth Zohore. Watmore and Tavernier both fit the bill. Browne will be desperate to prove he does too. A year ago Warnock was ready to let the former West Ham man leave, but he's changed the boss's mind with his attitude and application and the signs on the pitch were promising before the injury at Brentford.
It's hard to know what the future holds for Coulson. For whatever reason it just hasn't worked for him under Warnock so far. The boss has nothing bad to say about the 22-year-old and admires his enthusiasm, but he's struggled to nail down a role and a spot. It's an important summer for him.
Depth is an issue here. As Warnock has discussed, if he was to lose Watmore or Tavernier to injury, he'd have a problem. He needs numbers and options.
Up-front
It's no secret what Warnock wants. Strikers. Three of them.
The boss, in short, wants to completely overhaul his forward line. Of course, that begs the question - what for Chuba Akpom? The ex-Arsenal man had a tough first season at the club and the arrival of new strikers will push him down the pecking order. There's talk of quite considerable interest already.
James Collins was one of Warnock's top targets which tells us the type of striker he's looking for. The boss wants a rugged and physical frontman to lead his line, but someone - obviously - with an eye for goal as well. Michael Smith of Rotherham is on the list of potential targets. Warnock and the recruitment team have been talking for months about players and targets. The manager is desperate to have at least one of his new strikers through the door for the start of pre-season.
Famara Diedhiou has been linked since January, but if he wants to stay in the Championship he won't get the sort of money he was asking for at Bristol City.
Several other names have already been linked, some who are on the club's radar, others who aren't.
Josh Coburn emerged impressively in the final weeks of the season but it goes without saying Boro and Warnock will be extremely cautious with the teenager and won't expect too much too soon. Warnock might be reluctant to send the 18-year-old on loan in the first half of the season, not because he'll necessarily play a part for Boro but because he's coming on leaps and bounds from training with the first team squad on a daily basis.
What are your thoughts on the above and who would you like to see Boro (realistically) sign this summer? Have your say in the comments below.
