Tim Lincecum was demoted to the bullpen Monday. The question is: For how long?

In announcing that the two-time Cy Young Award winner would be replaced by Yusmeiro Petit in the rotation effective immediately, San Francisco Giants manager Bruce Bochy noted the new look will be re-evaluated after Petit's start Thursday against the Colorado Rockies.

Bochy said he believes Lincecum's recent struggles -- he has 8-1, 7-4 and 6-2 losses among his last six starts -- are mostly mechanical and can be worked out in a series of bullpen sessions. Skipping Lincecum at least once in the rotation gives him ample opportunity to space out three or four such sessions, Bochy noted.

Petit, who has retired 38 consecutive batters in relief, is assured just one start. However, it is interesting to note his second start would be Sept 2 at Colorado, and Lincecum has been particularly bad (3-6 with a 6.33 ERA) on the road.

The Rockies won the series opener between the teams Monday, taking a 3-2 win due in large part to a sloppy Giants defense that committed four errors.