Wolfsburg director of sport Klaus Allofs says the club are keen to hold on to both Bas Dost and Nicklas Bendtner.
Schalke ended a six-game winless run as Wolfsburg slipped to defeat, plus all the latest from the Bundesliga.
Hannover fought back from two goals down to take a point at second-placed Wolfsburg in a 2-2 draw.
Wolfsburg 1-0 defeat at Borussia Monchengladbach means Bayern Munich are Bundesliga champions.
Kevin de Bruyne rescued a point for Wolfsburg against Schalke as they lost ground on leaders Bayern Munich.
Wolfsburg lost ground on Bayern Munich at the top of the Bundesliga after being held to a 1-1 draw by Schalke.
Marek Hamsik scored twice as Napoli took a giant step towards the Europa League semi-finals by beating Wolfsburg 4-1 away.
Wolfsburg returned to within 10 points of Bundesliga leaders Bayern Munich with a 2-0 win in Hamburg.
Wolfsburg all but mathematically secured a Champions League spot with their 3-1 win over Stuttgart.
Robert Lewandowski was the difference in the German Klassiker, while there were wins for Monchengladbach and Leverkusen
Wolfsburg failed to make significant inroads on Bayern Munich at the top of the Bundesliga as they were held by Mainz.
Bayern Munich suffered their first home defeat of the season as Raffael's double secured a 2-0 win for Borussia Moenchengladbach.
Wolfsburg and Napoli meet for the first time in their history as the stand-out tie in the Europa League quarter-finals.
Wolfsburg and Borussia Monchengladbach boosted their Champions League ambitions with victories in the Bundesliga.
Wolfsburg saw off the threat of a spirited Freiburg side with a 3-0 win to return to within 11 points of Bayern Munich.
Wolfsburg, holders Sevilla and Napoli look on course for the Europa League quarter-finals after last-16 victories.
Augsburg got their push for a place in Europe back on track by becoming the first side to beat Wolfsburg in 2015.
Wolfsburg needed a second-half fightback to win 5-3 at Werder Bremen, while Borussia Monchengladbach beat Paderborn 2-0.
Wolfsburg refused to lie down as they inflicted the first defeat of the 2015 on Werder Bremen with a stunning 5-3 win.
Security will be tightened around Werder Bremen's game with Wolfsburg after police warned of a possible terrorist attack.