The defender signed in 2009 for a reported £17.5m fee by former Reds manager Rafa Benitez has looked somewhat lethargic as Brendan Rodgers' side looked to be homing in on a first Premier League title.
Johnson—then of Portsmouth—had been named in the PFA Team of the Year upon signing for the Reds on the back of an impressive 2008/09 season on the south coast, a season that included a stunning volley that was later goal of the season.
It appears, however, that in a Liverpool team that has leaked goals for fun, Johnson has been far from blameless in his contribution to a less-than-watertight defence.
The full-back's ability going forward has never been in question, but his ability to defend well on a regular basis has been one of debate for many a season.
As Liverpool capitulated at Selhurst Park on Monday, allowing Crystal Palace to level from 3-0 down, Johnson was abysmal as Palace wide-man Yannick Bolasie exposed the defender's frailties on more than one occasion.
As reported by Metro, the England man's dismal showing led to criticism from former Kop favourite Robbie Fowler and Sky Sports pundit Gary Neville, which Johnson took less than kindly to, retaliating via his personal Twitter account.
Johnson's form has been inconsistent for the majority of the season and was highlighted by this writer back in December as somebody who needed to improve as the season progressed.
Despite the defender receiving praise for his ability going forward, throughout the course of the season the former Chelsea man has managed only two assists in 28 appearances. He has also failed to get his name on the scoresheet despite mustering 19 shots on goal (via ESPN).
In contrast to fellow right-backs Pablo Zabaleta (1 goal, 5 assists, via ESPN), Branislav Ivanovic (3 goals, 1 assist, via ESPN) and Seamus Coleman (6 goals, 2 assists, via ESPN), Johnson's statistics make far from happy reading.
A renewal of Johnson's contract is something that does appear to be high on the list of Rodgers' priorities, but with the defender reportedly paid well over £100,000 per week, David Anderson of the Mirror claims that Liverpool will look to reduce the player's salary if a deal is to be agreed.
Johnson has been first-choice right-back for club and country for around five years but in that time has rarely faced serious competition for the position, either domestically or on the international stage.
Martin Kelly has arguably been Johnson's main competitor for the right-back position at Anfield while Tottenham's Kyle Walker has emerged as the most serious threat for the 29-year-old's England place.
It appears as though Walker—like Johnson—is more comfortable in the opposition's half of the pitch than he is in his own and often relies on his pace to get him out of trouble and recover from mistakes.
Manchester City's Micah Richards is a player who has previously filled England's right-back slot and is also a name that David Kent of the Mail Online reports interests Liverpool as a potential summer transfer target.
The muscular defender has found himself out of favour at the Etihad Stadium this season, starting only two Premier League games (via ESPN) and, according to Sky Sports, has told Manchester City he will seek pastures new.
Whether a move for Richards would signal the end of Johnson's career at Anfield obviously remains to be seen. The move may fail to make sense to some as Richards has not really looked close to dislodging Johnson from his England position for as long as memory serves.
What—in this writer's opinion—cannot be up for debate is that Johnson, without a shadow of a doubt, needs more competition for the right-back slot in Liverpool's starting lineup.
If, during the transfer window, the Reds add a new left-back to their ranks, then young Jon Flanagan—who has impressed during the second half of the season—may emerge as Johnson's main competitor for the position. Flanagan initially broke into the Reds side as a right-back before switching to left-back.
Johnson, of course, cannot solely be blamed for both Liverpool's defensive frailties throughout the course of the season or their collapse at Crystal Palace as their defence has struggled as a unit all campaign.
Daniel Agger has done okay when fit and selected, but only Martin Skrtel and Jon Flanagan of the Reds defenders have come through the season with any real credit.
Johnson has been a good servant to Liverpool, but the time for a change may well have come.
If reports from Jack De Menezes of the Independent are true that the Reds are looking at the possibility of signing Ashley Cole, coupled with the performances of Flanagan who—on form—deserves to stay in the side, Johnson's days could well be numbered.
What do you fans think? Is it time Johnson was replaced in the starting lineup? If so, who should the Reds look at as a potential replacement or do they already have one in Jon Flanagan?