There used to be a time period when Chelsea's full-back options were abundant. Branislav Ivanovic, Cesar Azpilicueta, Filipe Luis were all competing for a place in the backline at one point. But times have changed.
Antonio Conte's use of a 3-4-3 system at Chelsea, although it contributed to a highly successful season, left the full-back position in a complete mess. After Conte was sacked, Chelsea were left with Victor Moses and Marcos Alonso, who were then asked to slot in as full-backs by the then head coach Maurizio Sarri after a season full of games as wing-backs. It was the start of a big problem.
Sarri left the club and in came club legend, Frank Lampard who is yet to uncover a solution to the team's full-back problem. Azpilicueta, who excelled at the right centre-back role in Conte's three-man defence, has struggled to bomb up and down the right flank, which is the primary duty of a full-back in Lampard's proactive system. Reece James provided a good alternative to the English coach and the youngster has really come to terms with the pace of the Premier League after impressing with his loan spell at Wigan.
Azpilicueta offers more defensively but lacks the crossing ability of James which is a crucial trait for teams that rely on width. Against big teams, James' defensive awareness could be a problem.
On the other flank, the situation is worse. Neither Marcos Alonso nor Emerson has been able to cement the left-back slot. Alonso can come up with goals at crucial junctures but is otherwise lacklustre with his defending and tacking back. His crossing is poor as well.
Emerson showed a lot of promise early on this season but has been found wanting in big games against teams with good wide players. While his crossing is slightly better than that of Alonso, he lacks the Spaniard's confidence in making runs into the box and has a tendency to drop in and out of games.
Chelsea's last outing saw Alonso do well as a wing-back and even score a good goal against Tottenham Hotspur in the Premier League. Lampard has resorted to a three-man defence when under pressure to find a result and this could be one of the ways to deal with the full-back problem against FC Bayern in the upcoming UEFA Champions League Round-of-16 fixture as well.
Alonso is at his best as a wing-back and with Azpilicueta as the right-centre-back, Reece James's right flank also gets protection. But that system also relies on the striker's runs and hold-up play. Olivier Giroud was brilliant against Spurs but Tammy Abraham had returned to the bench after recovering from his injury and is likely to start in the mid-week fixture.
The full-back conundrum is not a good problem to have against teams like Bayern who have the ability to strike from the wings. But Lampard will need to tweak his tactics and come up with a solution if Chelsea are to progress.