Zaragoza's early-season form has been hard to evaluate so far to frustrate their former Sevilla boss Manolo Jimenez.
The Aragonese club have failed to score in all five of their Primera Division defeats, however, when they have found the net they have won on all three occasions.
It is hardly surprising then that Michel, whose Sevilla side sit level on points with champions Real Madrid in fifth, is expressing caution ahead of their trip north.
"They are a team that has been through a bad time and resolved it through character and competitiveness," Michel told a press conference.
"That is what Manolo's teams are all about so I think we'd best leave the statistics to one side.
"For us to go to La Romareda thinking it is going to be easy would be a big mistake."
Michel ruled out a move to replace long-term injury casualty Piotr Trochowski, who is in the United States after undergoing knee surgery.
The Germany international will miss the rest of the season and Michel hinted the injury could even end his career.
"We don't know how Trochowski's injury is going to turn out. It could force him out of the game but I spoke to him after the operation," he said.
"He is a stubborn German, very positive, ready for anything and is seeing what is the best way to go about his rehabilitation and what he will do about it.
"We have a 23-man squad but we won't be signing anyone unless we come across an absolute bargain or somebody on a free transfer. It is very difficult."
Zaragoza, who sit 14th, were 2-1 winners at Granada last weekend but will be without Ivan Obradovic who himself underwent knee surgery in Germany this week.
The Serbia international, who has made just one league appearance this term, is set to be sidelined for six months.