Schwartz waited until Friday, a day before Detroit hosts the Indianapolis Colts, to announce his decision.
He says not to read much into Culpepper starting, saying he could wait until just before the season opener to pick a starter.
The first-year coach says Culpepper will play into the second quarter when Stafford, the No. 1 pick in the NFL draft, will then play into the third.
Obviously, the Colts know who their QB is again this year.
Three-time MVP Peyton Manning looked ready for the regular season last week in a strong showing against the Eagles.
