Jan Vertonghen's face said it all in the 54th minute.
Level at 1-1 after Shane Long had cancelled out Tanguy Ndombele's early goal, Jose Mourinho decided to shake things up with his Tottenham side second best against Southampton.
Impressive on Sunday evening as they recorded a vital 2-0 win over Man City to keep their Champions League dreams alive, the Lilywhites were so far off the pace in the FA Cup fourth round replay and in real danger of crashing out.
Thankfully that didn't happen.
Starting with three at the back despite the success of a back four only a couple of days ago, Mourinho could see that it wasn't working for the Lilywhites and reacted by introducing January signing Gedson Fernandes to help the team out in midfield.
Vertonghen was the one to make way and he looked visibly distraught to be coming off.
Exiting behind the net as he was at the far side of the pitch, the 32-year-old seemed to take an age to get back to the dugout as he trudged along the sidelines incredibly slowly.
Mourinho gave him a quick pat on the back and the defender immediately took his seat.
Rather than putting his jacket on straightaway given the cold February weather, the Belgian international just sat there leaning forwards and didn't even glance up towards the pitch.
He looked like a man who knows his time at Spurs is up.
A mainstay at the back for the club ever since his move from Ajax in 2012, the 2019/20 season has been one to forget for the experienced player.
A shock omission from Mauricio Pochettino's squad on the opening day against Aston Villa due to tactical reasons, he has been in and out of the team ever since having been one of the first names on the teamsheet in the past.
Rewind the clock back 12 months and Vertonghen was absolutely outstanding in the 3-0 Champions League win over Borussia Dortmund with some marauding runs from left-back.
Teeing up Son Heung-min to volley home with a delightful cross, he also got his name on the scoresheet with a brilliant finish seven minutes from time.
The ex-Ajax man hasn't been able to hit those heights this year and it's almost like he has aged overnight and lost a yard of pace as he has been exposed a number of times since August.
Vertonghen turns 33 in April and it's clear to see that he isn't a long-term option for Mourinho going forwards.
The fact of the matter is he may not even be at the club come July as the head coach looks to build a team capable of challenging for trophies on all fronts.
Contract talk has dominated the headlines at Tottenham Hotspur Stadium over the past 12 months with Christian Eriksen, Toby Alderweireld and Vertonghen all entering the final year of their respective deals last summer.
Whereas Alderweireld has since extended his contract and Eriksen has moved on to Inter Milan rather than leaving on a free transfer, Vertonghen's future is still up in the air as he enters the final few months of his deal.
He can now talk to foreign clubs about a pre-contract agreement for next campaign and time is ticking for Spurs to extend his deal if they so wish.
His performances over the course of this season may indicate that he isn't going to be offered new terms to stay at the club after such a successful spell over the past eight years.
Davinson Sanchez has been preferred alongside Alderweireld by Mourinho since taking on the job in November, with Juan Foyth and Eric Dier also able to play there if required.
The emergence of Japhet Tanganga has also given the boss another option and, while he has been playing at left-back in Ben Davies' absence, the 20-year-old is a centre-back by trade and that's where he will end up for Tottenham over the coming years.
Unfortunately there comes a time with all players when they have to cut ties with their club, and that may be at the end of the season for Vertonghen.
Time waits for no one in football and the decision will ultimately come down to whether or not Mourinho sees him as part of his Tottenham revolution going forward.
Wednesday evening was an extremely tough one for the player to take and the substitution may have just signalled the beginning of the end of his glorious Tottenham career.
