These ratings are given to players based on their performance during the 2014-15 season and range from A+ (the best) to F (the worst). They are given based on how well they performed the role they were given, so they are not absolute but relative to expectation.
Rakitić came into the team somewhat underrated, with many Cules secretly hoping to have signed Toni Kroos instead. The Croatian had a fantastic season, however, and has surely converted most if not all his critics with his ability. He did it all - worked tirelessly covering the flank, put in goals, and made key passes. He never once complained, and got on well with everyone. His defining moment was opening the scoring in the Champions League final against Juventus, but one could argue his action in the second goal - letting Luis Suarez tap in the rebound when Rakitić had nearly the same claim to it - was just as emblematic. He was a support to the front three, but man, did he deliver on that. If there's one thing negative to say, it's that Raki can't control a match like Xavi. To be fair, no one can, and Luis Enrique didn't need him to. What remains to be seen is what he will be able to bring now that Xavi's gone.
With Xavi relegated to the bench, Iniesta took the role of the veteran in the middle of the pitch. Iniesta is not Xavi, he's more dynamic and more likely to dribble. He's also not Rakitic, and less of a natural fit for the box-to-box role. The system was not designed with Don Andres as the centerpiece, so it's natural he struggled at points. He didn't register nearly as many goals or assists as many liked, but Iniesta was never about numbers anyway. He came through at big moments, as is customary. At other points he spent more time defending than he's used to, but he coped well, despite his reputation as a slight player. Iniesta (or his use by Luis Enrique) was unfairly maligned in my opinion, but in the end, it was all smiles. (For a more in-depth exploration of this, read here.)
Like his mate Iniesta, Xavi had been called washed up by many. In fact, he was ready to leave European football last summer, and incredibly, many Cules said they wouldn't be too bothered by that. Luis Enrique deserves a lot of credit for convincing Xavi to stay and for using him effectively. The passmaster didn't have the legs to dominate match after match after match, but used in a reduced capacity, he was still effective. In fact, because of the rest, Xavi seemed more spry when he did play. His two Clasico matches against Real Madrid demonstrate the switch. In the first, he started and against a younger midfield, struggled to make his mark and Barcelona lost 1-3. But in the return fixture, he came off the bench and against tired opponents, calmed down the game and helped Barcelona secure a nervy 2-1 win.
The Brazilian came with big expectations after a successful loan spell at Celta under Lucho. Rafa struggled to put himself at the level of the big three midfielders, and was clearly a rotation option rather than a sure starter. Still, he grew up a lot and we saw his brilliance in flashes. Some felt disappointed he never fully took it to the next level, though a few niggling injuries didn't help his cause. The signing of Arda Turan suggests Lucho doesn't think Rafa is quite ready to be one of the main three midfielders, though surely a coach that has put his faith in him before knows he's not too far.
The other Croatian made a total of one appearance, from the bench. He's highly rated, but this season was all about adapting to the B team. He wasn't yet ready to contribute to the first team.
Grade: No grade, incomplete