The Magpies struggled to bring in top talent and even had to sell a few key youngsters to balance the books.
Shearer spoke on a podcast and talked about the disappointment at the club failing to bring in top targets, such as Crystal Palace’s Marc Guehi.
He stated on the Rest is Football podcast: “It's so disappointing that we didn't get the signing(s) over the line and, as I said, it doesn't reflect well on the Sporting Director or the Chief Executive.
"I don't think they've given Eddie (Howe) the best chance in going into the season with as good a squad as he would've wanted, and I don't think they've improved his squad from last season.
“When you look at the other clubs and what they've spent and what they've done, it's going to be really difficult for Newcastle to finish in the top four."