Davis, 26, came into Saturday hitting just .206/.328/.335 (89 OPS+) with nine home runs in 102 games. He was sent to Triple-A Las Vegas for about a month following a brutally slow start, but he has hit .269/.435/.446 with more walks (38) than strikeouts (35) in 47 games since returning.
Oblique injuries tend to linger and take time to heal, so Davis' season may be over if the strain is severe enough. Lucas Duda figures to get the majority of the playing time at first in his absence.
Davis will earn $3.125 million this year and could be a non-tender candidate this winter, though that seems unlikely given his age and 32 home runs in 2012.