Bayer Leverkusen's director of sport Rudi Voller has warned his club's striker Patrick Helmes to start delivering the goods on the pitch rather than complaining off it.

The 26-year-old was an unused substitute in Bayer's 1-1 draw with Bayern Munich last weekend and he left the BayArena in a rage, complaining of "double standards" in the way coach Jupp Heynckes made him wait so long before making a comeback after injury, yet brought Eren Derdiyok straight back into his side on Saturday.

Voller admitted he could understand the player's frustration, but he has arranged a meeting with the player and Heynckes to resolve the issue today.

"I would have preferred it if he had said something along the lines of, 'I have not been playing well recently and so I didn't deserve to start', but Patrick has seen things differently," the former Germany international told the Express newspaper.

God has given him this amazing shooting technique and pace, but he has got to take part more in the game and demand the ball more. Patrick is doing too little with his potential.
Rudi Voller on Patrick Helmes

"We are going to have to talk about it. God has given him this amazing shooting technique and pace, but he has got to take part more in the game and demand the ball more.

"Patrick is doing too little with his potential. He has got to do more, and it no longer has anything to do with his long injury break. Bayer Leverkusen are not Cologne. Our expectations are certainly different."

Helmes arrived from Cologne in 2008, scoring 21 goals in his first campaign, but his second season with the club was blighted by injury and he made only two starts.

Having lost his place to Swiss striker Derdiyok last term, he has struggled to win it back and seems uncertain about whether he wants to see out the rest of his contract until 2013. "It is up to Patrick himself where his career goes," added Voller.