Kaspars Gorkss, Joseph Mills and Adam Le Fondre are in line for their Reading home debuts.
Latvia international Gorkss, who played for his country in a European Championship qualifier against Georgia last Friday, returned to Berkshire fully fit.
And he will go into the matchday squad to face the Hornets alongside fellow defender Mills and striker Le Fondre.
Reading's other internationals - Hal Robson-Kanu, Simon Church, Adam Federici and Bongali Khumano - all came through the weekend unscathed.
Manager Brian McDermott has no injury worries ahead of the resumption of their Championship campaign.
Striker Matthieu Manset believes the squad's mood is positive, telling the club's official website: "The atmosphere is good. We are ready and will come back and start winning."
Watford boss Sean Dyche, meanwhile, has a welcome selection dilemma in attack for the trip to Reading.
Joe Garner is in line for his Hornets debut having arrived from Nottingham Forest on transfer deadline day, while Chris Iwelumo returns to the fold following hip and thigh problems.
The Hornets have struggled for goals over the start of the season but the 2-2 draw against Birmingham last time out marked the return to form of Marvin Sordell as he scored one and set up the other, before going on to find the net for England's Under-21s against Israel on Monday.
Andreas Weimann returned to Vicarage Road on loan from Aston Villa to partner Sordell in attack, and with Troy Deeney also available, Dyche has five strikers to choose from.
Stephen McGinn (knee) continues to be the only absentee.
