Excuse me. Correction. Gregson is not the Lestrade of anything. They are two different characters entirely! Gregson is, in fact, Lestrade's rival in the original canon. If Lestrade were to be cast, the two would have to be secret rivals, if the show bothered to stick somewhat close to canon, which it unfortunately doesn't, with the lack of Mycroft Holmes and, of course, Lestrade.
Excuse me. Apparently you can not read or look at the date the article was posted. Lestrade type character means Gregson is Holmes US cop equivalent of Lestrade. The article did not imply he would be Lestrade but a cop similar to what Lestrade was to Holmes in London. Plus the article was posted in March 2012 before the show was on and the proper pressers were released.