United have long been seeking a solution to their central midfield woes. Marouane Fellaini's £27.5m move from Everton has been a disaster, whilst Michael Carrick had an uncharacteristically poor season at Old Trafford. New manager Louis van Gaal simply had to get a midfielder who could get on the ball and create from a deep-lying role, and Herrera fits the bill perfectly. The 24-year-old may not have been capped by Spain yet, but he's been one of the stars of La Liga over the past couple of seasons, displaying skills and guile with the Basque outfit. A £29m fee is large considering that's almost what Cesc Fabregas was sold to Chelsea for, but Herrera fits what van Gaal and United are looking for perfectly – and his much more suited to playing as an '8' than Fellaini ever was.
£29m is fairly expensive given that Herrera hasn't really played at a truly elite level, scoring only five goals from midfield last season. It will no doubt take him some time to adjust to the more physical style of football in England, and he could even require someone more robust alongside him – hence United's pursuit of William Carvalho from Sporting Lisbon. Herrera isn't the marquee midfield signing that United were hoping for, and they may have been expecting more for the transfer fee they have paid.
Some United fans may have been underwhelmed at paying £29m for Herrera given that he's yet to really make himself a household name outside of Spain, but he has all the abilities that United should be looking for in midfield. He's far better suited to playing in the centre of the United midfield than Fellaini, and is now the Red Devils' most talented central midfield player given his vision and passing range. He could end up being the heir to Carrick in the United midfield, and if van Gaal can land someone more physical to do Herrera's dirty work, they could have the ideal midfield partnership on their hands.