Smith was placed on the 10-day injured list Saturday with a stress reaction in his left foot.
According to Tim Healey of Newsday, Smith said he was dealing with pain for about a week before heading for an MRI, which revealed the stress reaction. The injury could help explain Smith's struggles since the All-Star break, as he's hitting just .184 with a .547 OPS in 11 second-half games. Smith will undergo additional testing Monday, at which point a timetable for his return will hopefully emerge. Aaron Altherr was summoned from the minors to replace Smith on the roster, while J.D. Davis is starting in left field Saturday.