Bolton will be without striker Kevin Davies for up to three weeks after he chipped a bone in his foot.
Davies sustained the injury in The Trotters' FA Cup tie against Arsenal at Emirates Stadium on Sunday.
Despite playing on for the remainder of the game, the extent of the damage to his foot has been revealed.
Sam Allardyce could be lacking numbers up front after fellow striker Nicolas Anelka was forced off in the first half against Charlton on Wednesday.
Anelka is a major doubt for the weekend trip to Watford, so Kevin Nolan may have to be deployed in an attacking role again.
The Bolton captain moved up front following Anelka's withdrawal and could be set for an extended run in the position.
"I'll do a job anywhere for this club and I'll do it to the best of my capabilities," Nolan told the club's official website.
"I can play that role as well as playing in midfield. I was quite surprised (when I was moved forward) because I haven't played there all season."
El Hadji Diouf will return against The Hornets after serving a suspension, while Wednesday's goalscorer Henrik Pedersen may get a further chance in his favoured striker role.
Nolan has labelled the game against Watford a must-win after Bolton went all of January without claiming three Premiership points.
He said: "It's a tricky away game but three points is a must now because our last four games have been a disaster and we should have a lot more points.
"The minimum requirement on Saturday is we've got to go there and work hard, and if we do that then we can get three points."