Alvaro Morata will get a glimpse of what might have been as Real Madrid and Manchester United share the same pre-season facilities in Los Angeles.
Romelu Lukaku completed his big-money move to Old Trafford on Monday as Jose Mourinho's men swooped under the radar to snaffle the striker amid Chelsea's advances.
For much of the summer the Belgium international appeared destined for a return to Stamford Bridge, with Morata heading to United to fill the void left by Zlatan Ibrahimovic.
But the chance to sign Lukaku saw club sources confirm United had dropped their interest in the Spain international, leaving big question marks over the striker's immediate future.
Chelsea, spurned by Lukaku, is a possible destination for Morata, but first comes a trip to the United States after being included in 26-man squad heading on Real Madrid's pre-season tour.
Zinedine Zidane's side land in LA on Tuesday and, perhaps awkwardly for Morata, will be training a stone's throw from United, who are also using the facilities at UCLA this summer.
Mourinho's men have been at Drake Stadium since arriving in California, while Champions League winners Madrid will begin training on Wednesday within 200 metres of United at the college's North Athletic Field.
The teams will meet in the UEFA Super Cup next month as well as in the International Champions Cup on July 23, but whether Morata is still at the club by the time they meet in the Levi's Stadium friendly is another matter.
The Red Devils' first match of a hectic pre-season comes against the LA Galaxy on Saturday after a week of hard work on and off the field.
While Mourinho drills his troops Stateside, executive vice-chairman Ed Woodward has yet to join the travelling group as he works behind the scenes.
Press Association Sport understands United were targeting up to four high-profile summer acquisitions this summer, with Benfica defender Victor Lindelof and Everton frontman Lukaku the arrivals to date.
Chelsea defensive midfielder Nemanja Matic has been widely linked with United, while the club are understood to be interested in Tottenham's Eric Dier. The England international is believed to be open to a move to Old Trafford, but not willing to rock the boat.
A senior United source was dismissive of talk of a move for Monaco's Tiemoue Bakayoko, although Inter Milan's Ivan Perisic continues to be on the radar.
In terms of outgoings, Wayne Rooney, the club's all-time top scorer and captain, followed Ibrahimovic out of the Old Trafford exit door on Sunday to re-join Everton.
Josh Harrop, goalscorer on a dream United debut at the end of last season, turned down a new deal in favour of a move to Preston, while Regan Poole and Dean Henderson have joined Northampton and Shrewsbury on loan respectively.
The omission from United's pre-season tour of Adnan Januzaj, who spent last season on loan at Sunderland, underlines his place in Mourinho's thoughts.
Press Association Sport understands Real Sociedad are closing in on a deal, while Cameron Borthwick-Jackson is said to be of interest to Leeds.