Spurs' lack of defensive cover hurting their ability to rotate for big games
After Tottenham suffered the 2-1 Champions League defeat in Monaco which effectively ended their participation in the competition with one game still to play, Mauricio Pochettino pointedly stated: "Maybe we need to add more quality in the squad."
It seems reasonable to suggest the Argentine coach was particularly displeased with one or two of his reserve defenders that night -- specifically Kevin Wimmer and Kieran Trippier.
While Wimmer's recent spell on the sidelines is unremarkable given Jan Vertonghen's good form and Spurs' lack of cup ties, it is telling that Trippier has not played a single minute since the fateful trip to Monaco. Meanwhile Ben Davies, who was injured that night, has also been overlooked of late. The left-back's last start came in the dismal 1-0 defeat to Bayer Leverkusen at Wembley in early November and his previous one was the 2-1 loss to Liverpool in the League Cup, when Trippier was chosen on the other flank.
The pair's recent lack of action speaks volumes. Pochettino previously liked to rotate his full-backs but, notably, he picked his first-choice duo, Kyle Walker and Danny Rose, in five successive games during a busy fortnight before Christmas.
Perhaps the manager felt his favoured pair were too important to be rested -- a justifiable view given they have contributed a goal and four assists between them in the last three matches.
However, there is another side to the coin -- the gap between the first-choice players and the reserves has widened over the past 10 months, to the extent that Trippier and Davies can apparently no longer be trusted even to start home games against Hull or Burnley.
The lack of quality defensive cover, particularly at full-back, has become an issue. Pochettino caused consternation when he rested Walker and Vertonghen for the game in Monaco -- and he was wrong to do so -- but he was saving them for the match against Chelsea four days later.
It backfired. Spurs' defence disintegrated, the club lost their chance to reach the Champions League knockout stages and they then lost 2-1 at Chelsea anyway.
So a couple of weeks later Pochettino took a different approach. He took no chances for the final European game against CSKA Moscow, naming a strong line-up including Danny Rose, Walker and Vertonghen, despite the fact his side only needed a draw to qualify for the Europa League's round of 32, and the fact they were going to visit Manchester United three days afterwards.
Tottenham won 3-1, and the full-backs both had good games on the wide Wembley pitch -- indeed, Rose set up Harry Kane's goal -- but there was a cost. Spurs were defeated 1-0 at Old Trafford, when they lacked creativity and width. A tired Walker and Rose, understandably, were unable to maintain the levels they had produced earlier in the week.
Pochettino seems damned either way. Rest his star full-backs and he risks a setback, either due to a defensive lapse or a drop in the attacking threat from wide areas. However, keep picking them in every game and there is a good chance Walker and Rose will be less effective in the biggest games, when they often have to cover more ground to combine their attacking roles with defensive duties.
The situation cannot continue for long and Spurs will surely be looking for more effective reserves in the next two transfer windows.
In the meantime, Pochettino now faces another juggling act as Tottenham prepare to visit Watford on New Year's Day, three days before a giant home game against league leaders Chelsea, who lie 10 points ahead of them.
This time, though, the Spurs boss's hand is being forced somewhat when it comes to his decisions in defence. With Walker and Vertonghen both suspended against Watford, Pochettino will almost certainly have to throw Trippier and Wimmer back into action.
Watford are probably the ideal opponents for Trippier's return. Around time last year, on Dec. 28, the 26-year-old made his first Premier League start for Spurs at Vicarage Road and set up Son Heung-Min's late winner. He then went on to score the decisive goal in the return fixture as Spurs triumphed 1-0.
Pochettino used wing-backs for the first time at Watford last term and, having used the system again on a couple of occasions this campaign, he may opt for the same again on Sunday, allowing Trippier to focus on getting forward and putting in enticing deliveries from wide areas.
Of course, with Vertonghen absent, Spurs are missing a centre-back. However, Toby Alderweireld is set to return and Eric Dier and Wimmer could complete a back three, while Davies also plays on the left side of a three-man defence for Wales and might relish the chance to start in that role for his club.
Either way, Pochettino's back-up defenders need to step up and start proving they can be trusted -- not only in the cup competitions but in weeks such as these, when rotation against a mid-table side can improve the prospects of victory against a greater foe.
Ben is ESPN FC's Tottenham blogger. Follow on Twitter: @BenPearceSpurs.