"The Panther" has been in amazing form this season, by all accounts his last at Barcelona. He leads La Liga in save percentage. And despite a sometimes-leaky defense, Valdes is one of the favorites to take home another Zamora Trophy for best goals-against ratio in La Liga. At the weekend, he was faultless, stopping Rayo's long range drives, one-on-one chances, and even second-chance rebounds. He will need to be in top form again, especially improving on one of his weaknesses: claiming or punching set pieces.
Pique has been lambasted by his critics all season. Too slow, too unfocused, they say. Still, Pique has brought it lately - especially for the big games. His performance against Atletico Madrid to wrestle a clean sheet away from the current runners-up in La Liga was masterful. He'll need that form again as set pieces can be an Achilles' heel - and he'll need to be steady if City counter, as well.
Busquets was off color once, and Barcelona lost their first game at the Camp Nou. He wasn't his usual near-flawless self in the recent defeat to Valencia, and Barcelona seemed dysfunctional. That's how important he is to the Catalan machine. His interceptions and quick passing are consistently fantastic. But it may be his strength - an underrated characteristic of his - that will be necessary to fight a team which, as it is customary in meetings between Barca and EPL rivals, carries far more brawn.
Iniesta didn't really turn on the afterburners this season until recently. Against Atletico, he was in vintage form until he was kicked at so much he had to leave with an injury. And since his return, he's carried on as normal. He was sensational against Rayo at the weekend, effortlessly placing passes with pinpoint accuracy. For this match, Iniesta may be stuck out on the left wing, where he would face Pablo Zabaleta. Wherever he plays, he can be instrumental. Sometimes tactics and motivation can carry a team, at others, it's simply about your best players being at their best. Iniesta is one of the few who can turn a tie by himself.
Speaking of doing it alone, Messi comes in on a blazing-hot run of form. Some have questioned everything about him this season, but the chatter hardly seems to matter to him. Four of his last five goals have come from outside the area - some have been perfectly placed, bringing back the joy, some cannoned out of his left foot as he roared in celebration. His last was a chip over the keeper - from outside the box - with an audacious smile. Barcelona desperately need him to turn in another masterclass. Away matches in Europe have been a headache when Messi is not at his absolute best.
At his best, Silva is possibly City's best player. Problem is, he's not at his best always. But much like Iniesta, he can turn a game all on his own. Silva will also have a defensive responsibility. If he plays on the left side, he may have to chip in tracking Dani Alves; defending is not something he's especially known for. On offense and defense, Silva could prove crucial.
City's defense looks a lot better when the captain of the team, Kompany, is there to lead and organize. He also is a threat on corner-kicks. It will be interesting to see how Kompany copes with Messi's movement. He may not be the primary marker, but the organizational role will fall on him regardless.
An old foe of Barcelona's, Negredo knows what it's like to put one past Valdes. Negredo was not seen as a mega-signing in the summer, but he's proven to be extremely valuable. A compromise between a skilled, tricky forward and a pure #9, Negredo is in many ways perfectly suited to play against Barcelona. He will probably go toe-to-toe with Gerard Pique in one of the match's key battles.
A teammate of Messi's and Javier Mascherano's in the Argentine national team, Zabaleta is a class fullback. Versatile and well-balanced, Zabaleta might face varied threats today. Andres Iniesta could start on his flank, threatening him with his great vision and passing skills. Neymar, most likely coming on as a substitute, can beat him with quickness, even if the Brazilian is not 100%. Can he shut them down while still providing something going forward? A tall order, but Zabaleta may be up to the task.
Toure is still widely admired in Catalonia for being a charismatic, loyal player. Toure helped Barcelona to a Champions League win but lost his place to someone by the name of Busquets. Still, he gushes when he talks about his time at the Camp Nou, and still speaks Catalan. He's hard not to like, but Cules may not like him so much after this game. Compard to Busquets, the Ivorian offers more power and speed, though not quite the same technique and vision. He could bully the opposition if Barcelona let him. And it's not as if Toure is merely muscle, he is hardly lacking in other areas, and he can be a real pain on the counter. A team that can catch him out of position, though, can turn that advantage into his one weakness.