The Hungary international is a former Real Madrid Castilla star and has been influential in Mainz's success this season.
Reports in Hungary claim he could be set to return to one of Europe's big clubs, with Inter Milan and Liverpool linked, although his agent, Oliver Fischer, stressed there is no rush for him to move on.
"If there was an offer then it's likely that we would consider it," he told Nemzeti Sport.
"But at the moment the most important thing is that Szalai is happy to play at his present team.
"No-one contests that Internazionale are a big club but the player is still very young, this is his first full season at Mainz and he has to progress."