Mikel Arteta revealed Shkodran Mustafi faces a long injury lay-off after ruling the Arsenal defender out of next weekend's FA Cup final.
Mustafi missed the Gunners' white-knuckle ride which sent Watford down, and they were fortunate not to squander a three-goal lead.
Now manager Arteta is short of defensive options for the Wembley showpiece which offers Arsenal one last shot at European football next season.
And he admitted his shortage of fit defenders is likely to force his hand in the transfer market.
Arteta said of Mustafi's setback: “It looks a really nasty injury again.
"We have lost Calum Chambers the week after I arrived here, we lost Pablo as well for three months.
“Now we’ve lost Musti so at the back we’re really stretched and short.
"Musti has been playing really consistently and at a really good level with me recently.”
Asked if it was likely to be a long-term lay-off, Arteta nodded: “I think so – he will miss the start of next season.
“He pulled the tendon off the bone in his hamstring and that’s normally a lot of weeks.
“That's three central defenders who are not available and we haven’t had them available for a long time during the season.
We will have to address that.”
Two first-half strikes from 27-goal top scorer Pierre-Emerick Aubameyang and Kieran Tierney's first goal for the Gunners proved just enough to send spirited Watford down.
Sign up to the Mirror Football email here for the latest news and transfer gossip.
