I'd say Carrick is third-tier, if we're doing it like that:
Top tier - Xavi, Iniesta, Pirlo and Scholes at their best
2nd tier - Alonso, Fabregas (currently), Yaya Toure, Schweinsteiger, Sneijder, Gerrard and Essien at their best
3rd tier - Carrick, Van Bommel, Ambrosini
4th tier - Fletcher, Barry, Song, Lucas Leiva (currently)
Tiers of a clown - Adam, Henderson, Spearing
Modric is somewhere between 3 and 2, as was Lampard at his best.
...Yeah there are clearly gradations within each tier. I'd say Scholes and Pirlo are well down the bottom of tier 1, with the likes of Zidane at the top.