Aberdeen finished second in the Scottish Premiership last season after ending up third in the table during the 2013-14 campaign.
Derek McInnes’s side are second in the standings at the moment, and they are set to stay there until the end of the season.
Rangers easily won the Scottish Championship title this campaign and will feature in the Scottish Premiership next season.
Former Rangers and Heart of Midlothian winger McCann has suggested that for Aberdeen to finish second again next season, they have to spend big money in the summer transfer window due to the competition they will face from the Gers.
“Next season, Rangers [will be] back with a big budget, as Derek (McInnes) said, and he has to be given some more money because he can’t have another season looking behind him thinking ‘I’ve lost a couple of key players, who do I look to?’” the former Scotland international told The Glasgow Evening Times.
Rangers will be expected by many to challenge Old Firm rivals Celtic for the Scottish Premiership title next season.
The Gers will be making signings in the summer transfer window in order to strengthen their squad, and they will be hoping to finish at least second in the league during the 2016-17 campaign.