Eintracht Frankfurt's first-choice goalkeeper Kevin Trapp is set to miss the rest of the season after breaking his left hand while filming an advert.
Trapp tripped and fell during a publicity shoot for the Germany Under-21 team on Monday.
Scans have revealed the 22-year-old suffered a break that is set to jeopardise Eintracht's European ambitions.
"The injury to Kevin Trapp is unfortunate for Eintracht Frankfurt and certainly a major setback," Eintracht chief executive Heribert Bruchhagen told the club's website.
"The medical prognosis is especially bitter. The probability that Trapp will play again is very low.
"We will discuss together with the German Football Association and analyse exactly how the accident happened."
Trapp offered his version of events to Bild, saying: "I don't know what happened. I started walking and all of a sudden I was down on the ground."
His agent, Dirk Hebel, added: "Somebody caught Kevin's heels and he slipped."
Trapp, who is to have surgery on Friday, has been a key part in Eintracht's unexpected fight for European football after only returning to the Bundesliga this season.
The club currently sit fourth although they have failed to win in their past six league games.
Trapp is likely to be replaced by 38-year-old Macedonian goalkeeper Oka Nikolov, who has made more than 350 appearances for the club.
Szczesny was axed for the Champions League game against Bayern Munich last week, with Wenger claiming the 22-year-old had been "mentally affected" by the number of games played.
The Poland international was then put on the bench for the Premier League win at Swansea, where Lukasz Fabianski kept a second consecutive clean sheet.
Szczesny has joined up with the Poland squad ahead of their World Cup Group H qualifiers against Ukraine and San Marino, but Southampton keeper Artur Boruc is expected to be first choice, with Brighton's Tomasz Kuszczak providing support.
Maciej Szczesny - who won seven caps for Poland and helped Legia Warsaw reach the quarter-finals of the 1995-96 Champions League - feels Wenger needs to look at how he handled his son, who has been hampered by a series of niggling injury problems.
In an interview with Poland's leading sport daily paper Przeglad Sportowy, the senior Szczesny said: "Wenger already started to look for the scapegoat. It is not the way the boss should behave.
"Wojciech has had two serious injuries. He played with one in April and May (last year). He shouldn't have agreed to play that time, but the coach insisted.
"Wojciech did not train the whole week and then a warm up on Friday and played the match on Saturday. He was naturally more susceptible to minor injuries and his form was going down.
"Wenger was playing with the young man's good health and Wojciech agreed foolishly.
"In my opinion Mr Wenger messed up a lot in April and May. I don't blame the young man who went along with his coach, his current lack of form is a result of those two months.
"Then in August there was a foot (ankle) injury after which he played almost instantly.
"After seven weeks out Wojciech trained for just seven days and played the match. How on earth can he be on his highest form?"
Despite taking Szczesny out of the firing line and warning no-one can be guaranteed of a place in the team - not even captain Thomas Vermaelen - Wenger has said Szczesny is part of his long-term plans, having brought the youngster through the Arsenal Academy after signing from hometown side Legia Warsaw in 2006.
Szczesny Snr is confident his son will soon establish himself as the Arsenal number one again.
"This last period has not been successful for Wojciech, the fact that Arsene Wenger did not take him to Munich shows something," Maciej Szczesny added.
"However, I think my son can be the number one (Arsenal) keeper over 10 years, he just needs to come back to form and then a situation where we can stop to wonder who will stand between the posts."
