Yeah, his 143 receptions were a result of Edge's lack of performance last year, but so were his (only) 10 TDs. He'll get fewer catches this year. However, with the threat of the run, Indy's play action will be more effective this year allowing Marvin to nab a few more TDs.
I wouldn't worry. Look at his stats over the past 5 years. No one in fantasy football is as consistent as Harrison. Well, maybe Manning is as consistent.