The former England manager's future at City is up in the air after Eriksson's agent conceded it looked likely he would be leaving the club.
Grip, who is part of Eriksson's backroom staff at Eastlands, is shocked that Shinawatra wants to replace Eriksson and has accused the City owner of showing a lack of patience.
"We are left with the two games. They probably think we've done a poor job," Grip told Sportbladet.
"We think we've done it well. It has been going a little bit worse after Christmas but it's always going up and down in the football and the Premier league is a marathon. It takes time to build up a team."
When asked if Shinawatra was showing a lack of patience, Grip said: "I would think that it has something to do with that."
If Eriksson does lose his job at City, Grip says his fellow Swede will not be short of offers from other clubs.
"No [more news] it has happened so fast," added Grip.
"Sven will get new offers, I'm convinced about it. But nothing is happening before the season is over."