The defender has been training with Mark Warburton's Glasgow Rangers side in the hope of earning a deal at Ibrox.
Philippe Senderos' countryman Ramon Vega has told the Daily Express that the one concern he has about the centre-back is his fitness levels as he attempts to prove to Mark Warburton that he deserves a Rangers contract.
The 31-year-old has joined the Light Blues on trial, the Express claims, after leaving Grasshoppers following the end of his short-term deal with the club.
And Vega - who once enjoyed a brief loan spell with the Gers' bitter rivals back in 2000-01 - has suggested that while the former Premier League defender will offer a lot if he did move to Ibrox permanently, he did admit that he was concerned about whether he can handle the demands of the Scottish Premiership.
"The Rangers manager will see Philippe's experience, the clubs he has played for and you can see why he would appeal to them," he told the Express.
"If you have experience then you can offer a lot on the pitch and he can help bring some of the younger players at Rangers along.
"If he is fit then he could be an asset to Rangers, but the key is fitness."
Rangers manager Mark Warburton
There is no doubt that Warburton needs to add some extra depth at the back. Having failed to extend Dominic Ball's loan deal beyond last season - though the Express claims they did try - Rangers had begun the summer with just Danny Wilson and Rob Kiernan as natural options in the centre.
And while they have since added Clint Hill and David Bates during the window, both men are arguably short-term options, with the former well into the twilight of his playing career and the latter being on loan and working predominantly amongst the academy ranks.
But despite the lack of options, Warburton has proved that he is not prepared to just hand deals over if he is not convinced about the player, not matter how impressive their CV. Oguchi Onyewu was unable to earn a contract after joining the club on trial earlier in the summer.
But despite the manager's ability to be ruthless if necessary, Vega is clearly confident that if Senderos can show that he is fit enough to handle the top flight, then he has more than enough ability to enjoy a successful spell in Scotland.