A 2-2 draw at Burnley on Saturday left Spurs with two wins from their last 14 Premier League matches as pressure grows on Frank, who many fans are crying out to be sacked as soon as possible.
Frank got some relief with the Champions League win against Borussia Dortmund, but Premier League results are far from satisfactory for the Danish head coach, who could be let go this week.
Speaking to Grosvenor Casinos, Saha says hiring Frank was a mistake and the club should have stuck with former manager Ange Postecoglou.
"Spurs are struggling and the style of play looks static, it puts people under pressure. It's sad to see.
"Looking at the squad, I don't think it's a fantastic one. It hasn't been renewed in the way a club of this size, with these kinds of ambitions, should have done.
"They skipped a few transfer windows and didn't bring in the type of players that could fill the enormous gap left by the departure of Harry Kane.
"Many of those tactical choices haven't helped at all. I don't understand the sacking of Ange in all honesty. It's sad for Spurs. I don't think that was a step forward.
"Now they have a manager, they have to back him. It's easy to be upset when your club isn't doing well. You have to accept your choices sometimes and give the manager time to build something. There are moments when it's extremely frustrating because you're losing money and credibility, but sacking manager after manager doesn't help."
After facing Frankfurt in the Champions League this week, Spurs are at home to Manchester City before a visit to Manchester United in what are tough fixtures for Frank who, whose head is on the chopping block at the moment.