Keller wary of struggling Bremen
Schalke coach Jens Keller has pinpointed the attacking threat of Werder Bremen as a cause for concern ahead of their Bundesliga meeting.
Keller's men, who are looking to consolidate fourth position on the table, make the trip to Bremen and face a side in desperate need of maximum points.
Bremen sit just seven points clear of the relegation play-off position, having gone seven games without a win.
Thomas Schaaf's team also boast the league's worst defence, with a whopping 52 goals conceded in 27 games to date, but Keller is still wary of a side featuring the likes of Marko Arnautovic and Kevin De Bruyne.
"Whoever takes a look at the squad of Werder Bremen sees a lot of quality," Keller told reporters.
"Especially in attack, they have good players with individual quality. Obviously they have some weaknesses in defence and concede goals.
"But with Arnautovic, (Eljero) Elia, De Bruyne and (Aaron) Hunt they have players who can decide a game alone, they are very dangerous."
Bremen are looking for their first league victory since February 10, when they disposed of Stuttgart 4-1 away from home, but Keller is expecting a tough challenge at Weserstadion, regardless of the home team's dire recent results.
"They are lacking a bit of form at the moment," he said.
"But I think they want to turn that around against us on the weekend, in front of their home crowd.
"So I expect they are highly motivated."
Meanwhile, Schalke general manager Horst Heldt has called for focus from his side as the domestic campaign draws to a close, with European football the prize on offer.
The 2010/11 UEFA Champions League semi-finalists bowed out of the same competition last month, falling to Turkish giants Galatasaray 4-3 on aggregate in the first knockout phase.
Schalke have improved considerably in the Bundesliga early in 2013, but can ill afford many poor results, with only three points separating fourth and seventh.
"We have no internationals until the end of the season and no matches in Europe anymore, we only have the Bundesliga," Heldt said.
"So now we need to be focused in every game to be successful and I think this is a good chance for us.
"If I hear from the players, that they want to play in the CL, then I expect them to push back their personal interests."