With two weeks left to go before the start of the season, Manchester United have so far only signed players for two of the four positions that José Mourinho deemed to be lacking. A replacement in the lead striker role and an upgrade extra body in the middle of the defense have been secured. Still outstanding are a defensive midfielder and a winger, the two signings that Mourinho has confirmed that are on his list. Ivan Perišić and Nemanja Matić - neither apparent first choices - are the most often mooted names, and it would be a surprise if at least one isn’t signed before the start of the season.

Relative to some of their domestic and European rivals, however, United are having a low-key summer. The potential deals for Matić and Perišić seem to have been dragging on forever, but United face little competition for either player.

Elsewhere in Europe, some bigger and more dramatic transfer business could still yet impact United’s signings (or lack thereof) this summer. At the top end of the football transfer market, mega-transfers can have a domino effect. One big club signs a big player from another big club, and suddenly somebody has tens of millions of euros burning a whole in their pocket, and someone else starts nervously edging a star player out of the door to balance the books. Let’s poke our noses into other people’s business and see how these potential deals could have a knock-on effect on the Reds.

Kylian Mbappé to Real Madrid

A young man with one season of senior football under his belt could be on the move this summer for the price of two Paul Pogbas, who himself cost two Zinedine Zidanes, and look, that’s just the market these days. Real Madrid, who must have the newest, shiniest thing all the time, are reportedly in pole position to sign’s Monaco’s phenom. Even for Real Madrid, though, the financial and footballing math doesn’t quite work this time. Though still just a teenager, Mbappé isn’t coming to the Spanish capital to kick his heels on the bench, especially not at the cost of (gulp) €180,000,000.

Even before the addition of the young striker, manager Zinedine Zidane faces something a selection dilemma. In Gareth Bale’s injury absence towards the end of last season, Isco made himself undroppable, while neatly fitting behind Cristiano Ronaldo, who is essentially a striker these days. So, with the addition of yet another attacker, Bale starts to look like the odd man out. Long coveted by United, he fills a need that Mourinho has expressed, will be marketing dream (A Welsh left-footer who conveniently has the right boot sponsor? CHA-CHING!), and Madrid will be willing to do business.

So far though, Mourinho doesn’t want to waste time chasing the impossible, Bale is happy where he is, and until Mbappé actually signs, this one may go nowhere.

Neymar to PSG

Another long- coveted attacker at one of La Liga’s big two could be on the move this summer, but apparently not to United. Neymar has upgraded his now annual flirting with PSG to scandalous levels (A training ground bust up?! You sly devil.), and this move feels like it could actually happen. Neymar either wants to get out of Messi’s shadow, or he wants Barcelona to give him Messi’s wages, but PSG believe that they have a chance to sign the Brazilian for real this time.

We’re not quite sure how Financial Fair Play works - although it can’t be working very well if PSG can pay Neymar’s buyout clause and Manchester City can spend 75-odd million on two crap fullbacks - but we have to assume that this move will involve some checkbook balancing. €222m is an eye-watering amount for one player, and it’s the kind of expense that could tempt PSG to part with another of their stars.

United need a holding midfielder. PSG may need to raise some transfer funds. One of the best metronomes in world football happens to play for PSG, and he just changed agents, hiring our new best mate Mino Raiola. Ipso facto, Marco Verratti to Manchester United makes a load of sense. The minute that the Neymar deal is agreed, United should be on the phone with Raiola getting the wheels in motion.

Kylian Mbappé to Real Madrid (again)

Gareth Bale possibly being for sale isn’t the only domino that could fall in Mbappé’s transfer. And no, we don’t mean United putting in a cheeky bid for Marco Asensio. Although that wouldn’t be a bad idea either. On the other end of the transaction, Monaco would be flush with cash from selling off half last season’s team to the tune of about €300m. Even in the midst of this fire sale of all their young talent, there will be a ceiling on how much they’re willing to give up.

If Arsenal also somehow manage to wriggle Thomas Lemar from Monaco’s grip, we’ll almost certainly have to say goodbye to TBB’s favorite rumored transfer target: Fabinho. Pour one out in the comments section.

What other domino effects could there be in this summer’s market? Have your say in the comments.