Defender Yennaris is back in contention after overcoming a dead leg that has seen him miss the last two games.
Midfielder Saunders is ready to make his first appearance of the season having worked his way back to fitness following his return from a loan spell with Wycombe last term.
Still on the sidelines are Marcos Tebar (hamstring), Josh McEachran (foot), Jota (ankle), Andreas Bjelland and Scott Hogan (both knee).
Paulo Hurtado is unlikely to make his Reading debut until after the international break as he lacks match fitness.
Pavel Pogrebnyak, who has yet to feature this season, will also miss the trip as he is still recovering from an ankle injury.
Dominic Samuel remains on the sidelines with a knee injury, although the extent of the problem suffered in the Capital One Cup tie at Colchester on August 11 is not as bad as first feared. He is likely to be out for two months.
Garath McCleary and Nick Blackman, who was allegedly subjected to racist abuse during Tuesday’s match against Portsmouth, are both in line to start.