As exciting as the prospect of adding attackers is, it's impossible to argue that Liverpool doesn't need to add to the back line. While most of the transfer chatter for Liverpool's defense has been focused on the centre back position, improved depth at fullback seems just as important after some of the travails at the position last season. Having already discussed potential attacking targets for the club after missing out on Henrikh Mkhitaryan, let's take a look at some fullbacks that might (or maybe should) be on the club's radar.
While left back is certainly the priority, it couldn't hurt to find a way to improve depth at right back depth as well. It was obvious as the season wore on that Glen Johnson's heavy usage was taking a heavy toll on him, but with only the ever-injured Martin Kelly and Andre Wisdom's inexperience at the position to back him up, Brendan Rodgers had little choice but to lean heavily on England's primary right back, especially as he represented the primary backup at left back as well. Upgrading the depth at right back would also allow Kelly and Wisdom to focus more on playing centre back, which many (myself included) believe to be the ultimate position of both players.
With that in mind, a player who can play in both spots might be ideal, although players who are truly effective at both fullback spots are few and far between. Among those who are reportedly available and of sufficient quality to provide good depth for Liverpool is Fabian Johnson, a German-born American international who is currently plying his trade with Hoffenheim in the Bundesliga. Johnson has explosive pace and is fully capable of joining the attack, but suffers from bouts of wandering attention that have left him exposed defensively at times. I wouldn't consider him an ideal candidate, but if Rodgers is looking strictly for a backup at both spots who can handle himself in Cups and against weaker league opponents, then he could do a lot worse than Johnson.
If Rodgers wanted to go more for a straight left back to push Enrique for a starting spot, or at worst be a quality backup, there's a few potentially-available names to consider. Such a player would need to push forward and support the attack better than Enrique generally does. Don't get me wrong, Enrique can put in a good pass now and then, but he's only an average crosser of the ball and his overall contributions in the final third are often inconsistent. It would also be helpful if anyone brought in can have an awareness of space behind him, so that he doesn't push too far forward and be left hopelessly out of position on a counter-attack.
Stefan Radu (Lazio) is a good defender along the left who's capable of pushing forward at times, though he's had a string of injuries over the years that have kept his stock down. Alvaro Pereira (Inter) is a great marauder who has the work-rate and wherewithal to keep himself from getting caught too far up the field very often, though his availability might be in question. That said, Inter is not in good financial shape, and any sort of decent enough should at least tempt them.
Ryan Bertrand has been connected to Liverpool recently in the media. I'm not sure I buy it, as he's Chelsea's only backup to a fading Ashley Cole right now, with Patrick Van Aanholt having returned to Vitesse on loan. I'm also not convinced as to how good he is now or will be; he's a fine enough backup, but I don't think he can meaningfully push Enrique for time on the pitch. Given his price (believed to be somewhere in the range of £7-10 million), I'd rather look elsewhere.
A more dark-horse option would be Ivan Strinic, of Dnipro in the Ukrainian Premier League. I've seen him play a few times, and he's always done well against the better teams in Europe (Dnipro is a regular in the Europa League). He's pacy, and picks his spots well getting forward. Obviously it's hard to know if he'd make the jump well, but he shouldn't cost too much, making the risk a little bit easier to stomach.
If Liverpool would rather bring in a young fullback with potential, but would not be out of place getting semi-regular playing time, two names come to mind: Wolfsburg's Ricarcdo Rodriguez and PSV's Jetro Willems. Willems, 19, looked overwhelmed in the Euros last season with Holland's senior squad, but seems to be better off for the experience. He started 25 matches for PSV last season, and would have started more if not for a pair of injuries that kept him out for seven matches. He's very well-rounded, and shows an advanced feeling for positioning for his age. Rodriguez, 20, has a similar profile, but is still a bit more raw and might be harder to pry away from Wolfsburg.
Should Rodgers and his staff desire to look for a right-back to strengthen the depth there, it's likely that they'll look for the right-side equivalent of Willems or Rodriguez. The main name that springs to mind there is Adam Matthews of Celtic. He's another young marauder with much to learn in the defensive end of the position, but he's shown enough promise to warrant consideration. Daniel Opare of Standard Liege in Belgium is a more experienced option, and has the added benefit of being somewhat capable on the left side as well. Plus, he's rumored to be a target of Tottenham's, and boy wouldn't it be nice to be on that side of a snatch-and-grab for once.
Hopefully this has helped give you a better idea of the kinds of players Liverpool can turn to in order to in order to bolster the fullback position. Later this week, I'll take a look at center backs who can play alongside Daniel Agger.