Maierhofer played for over half an hour during Wolves' 2-0 win over Real Zaragoza on Saturday and Mick McCarthy picked him out as the star player.
He was made available for transfer at the end of last season having played just eight times for the club in almost two years but the 28-year-old still has a chance of making McCarthy's 25-man squad for the new Premier League season.
He said in the Express & Star: "We made a lot of substitutions and Stefan was among the pick of them - he was excellent.
"I bought him to do that and if he continues to do that then he will be in my squad."
However, German club Eintracht Frankfurt are interested in the Austrian striker, with sporting director Bruno Hubner commenting: "A guy almost two metres tall can win you the odd game through his dynamism and heading ability.
"I can't deny it, he's an interesting player."
Source: Team Talk
Source: Team Talk