The move could be considered a move up, as Williams finished ninth out of 11 teams in the Constructors' Championship, while Toro Rosso finished eighth.
Briton Smedley, 40, once worked with the Williams touring car outfit. He has been linked with a return to the team for some time, long before Felipe Massa emerged as a candidate for a 2014 race seat.
While the presence of his longtime pal Massa clearly won't hurt, as chief race engineer Smedley will have responsibility for both cars, and thus won't be the man talking to the Brazilian on the radio.
Meanwhile the 40-year-old Pujolar previously worked with Red Bull motorsport boss Helmut Marko at the Austrian's RSM F3000 team, back in 2000.
The Spanish native first became involved in F1 as an assistant race engineer at Jaguar in 2002. He then joined Williams as a performance engineer in 2003, and he was promoted to race engineer in 2004, initially working with Juan Pablo Montoya.
After a brief spell at HRT in 2010 he rejoined Williams for 2011, and he was Pastor Maldonado's engineer when the Venezuelan won the Spanish GP last year. This season he was promoted to the role of chief race engineer. AutoWeek