Mainz coach Martin Schmidt is unsure about an immediate debut for Stoke City striker Bojan Krkic.
Krkic joined Mainz in a straight loan this week, but Schmidt says he may hold back the Spaniard.
"He is still in the learning phase, we will tackle the story with care," said the coach.
"There are small things that he has to get used to. He plays for the first time for a small club, he must know how Mainz ticks.
"The mood is different through him. It has a good external effect. Through his commitment, we were able to increase the performance pressure non-verbally. And he is top linguistically. This accelerates his learning phase."