Louis Van Gaal's side suffered an embarrassing 2-1 defeat to Bournemouth on Saturday which has the the Red Devils without a win in their last five games in all competitions.
Shearer has added to the criticism of van Gaal for fielding inexperienced players such as Cameron Borthwick-Jackson over the likes of Morgan Schneiderlin, Phil Jones and Ashley Young in the recent defeats.
"It was a huge win for Bournemouth on Saturday getting the better of Manchester United in the Premier League, but when I saw the teams before the game, I wasn't actually surprised as it may have been Manchester United football club but it wasn't a 'Manchester United team," Shearer told Coral.co.uk.
"There was no leadership or organisation from Manchester United.
"I was surprised with the team Van Gaal fielded, especially when you look at their bench and the experience they had on there with Schneiderlin, Jones and Young.
"I am not sure what has gone on with the manager and Ashley Young because he has played him at full-back a lot this season but then to throw the inexperienced Borthwick-Jackson in, not only in the Champions League, but also on Saturday, was odd.
"He seemed to struggle at left-back where Young could have comfortably played. I also felt McNair struggled in the middle of defence where Jones could have played. If they are fit to be on the bench, then they certainly can start the game."