BERLIN, Aug 30 (Reuters) - Franck Ribery, Luca Toni and Miroslav Klose, the trio of new signings who have brought such verve to Bayern Munich's attack this season, are all doubtful for Sunday's trip to Hamburg SV.
French midfielder Ribery has a calf muscle strain after taking a series of heavy challenges as Bayern made it three wins out of three against Hanover last weekend and took a two-point lead in the process.
Germany international Klose is still struggling with a knee injury, while his Italian striker partner Toni suffered a thigh strain as he scored the opening goal against Hanover.
It is all shaping up to be a tricky weekend for coach Ottmar Hitzfeld, who may have to recall Lukas Podolski ahead of schedule to lead the forward line.
Schalke 04, four points behind Bayern, have the chance to make up three of those by winning at home to Bayer Leverkusen on Friday.
Bayern could even lose their lead in the table on Saturday when the trio of teams on seven points, Arminia Bielefeld, VfL Bochum and Eintracht Frankfurt, are all in action.
Even at full strength, a match away to Hamburg represents one of the trickiest fixtures of the season for Bayern and manager Uli Hoeness has been trying to lower expectations.
'The way we've started has been fantastic - a dream,' Hoeness told Munich's tz newspaper this week. 'But we know the idea that we're unbeatable is just crazy. We're there to be beaten.'
Bayern's advantage is that Hamburg will not have much time to recover from a UEFA Cup qualifier against Honved on Thursday.
While Bayern could afford to drop points against Hamburg and still be considreed strong favourites for the title, Schalke need nothing less than victory over Leverkusen.
Last season's runners-up are still unbeaten but with just one win and two draws it has hardly been a convincing start.
On Friday they could be without captain Marcelo Bordon, who is doubtful after taking a blow to the knee in training on Wednesday.
'He'll have intensive treatment and I hope he'll but fit,' coach Mirko Slomka told reporters.
The race for provisional top spot on Saturday will test the away form of the season's three surprise packages.
Bielefeld travel to face Duisburg, Bochum are away to Hanover and Frankfurt have the toughest game away to Werder Bremen, who defeated Dinamo Zagreb 3-2 on Wednesday to enter the Champions League group stages.
Champions VfB Stuttgart, who like Werder won for the first time last weekend, are in action on Sunday, away to Karlsruhe.