Alan Pardew's men sit ninth in the Premier League after surprise wins over Chelsea and Tottenham in the last fortnight.
But while Newcastle have already beaten two of the teams tipped to finish in the top four, Pardew's side have also slipped to disappointing defeats to the likes of Hull City and fierce local rivals Sunderland.
And Shearer - who scored 206 goals for Newcastle in a 10-year spell - believes the club's fortunes will continue to fluctuate throughout the campaign.
"That's what Newcastle will do this season. They'll have some great results and they'll have some poor results," he told talkSPORT.
"If you put their first 11 out then they will be a match for anyone because the spine down the middle of (Tim) Krul, (Fabricio) Coloccini, (Yohan) Cabaye and (Loic) Remy, who has started the season in fantastic form, there is not many better than that."
Pardew has left Hatem Ben Arfa out of Newcastle's last two victories, an omission that Shearer - manager of Newcastle for a brief spell in 2009 - understands.
"I understand why (Ben Arfa was left out) to be honest," Shearer added. "He is not going to give you 100 per cent workrate and when you go to Tottenham and when you play Chelsea, you understand you are not going to have as much possession as those guys.
"You need 11 guys who are going to work very hard for you and he won't work hard for you. He will give you other things when you are playing lesser teams and he will produce fantastic finishes and passes.
"You say to me great players what is the minimum you should always give, you should never ever praise any player for hard work because it should be a given.
"He doesn't work as hard as others but he's got skills others haven't."
