I say that evolution is an improbable theory in light of Holmes’s dictum that "when you have excluded the impossible, whatever remains, however improbable, must be the truth." Excluding god as impossible leaves us with the improbable but true theory of evolution. Fail to exclude god and evolution is nothing but an improbable theory.
Theism implies some form of creationism but not necessarily the ‘on the 7th day he rested’ version. One could of course so weaken theism as to make it consistent with anything (e.g. deism) but in practice this is amounts to atheism or agnosticism. Any theism worth its name, i.e. postulating a god that works his or her ways in the world today is bound to be inconsistent with evolution. It makes no sense to assume a god that intervenes to answer prayer but who never has done any genetic engineering.