Considering we currently have:
3 PGs (IT, Smart, Rozier)
2 PFs (Horford, Theis)
2 Cs (Zizic, Baynes)
and 8 SFs (everyone else)
....I'd say yeah, Brown will play some SG, especially considering he's the smallest/quickest of our forwards. Smart can't play all the minutes. And obviously when in the backcourt with IT he might have to guard the opposing PG.
You have to expect Rozier and Brown would be our 3rd and 4th guards while Smart and IT play major minutes and Hayward, Crowder and Morris split all the forward minutes (with Tatum or Yabu trying to earn whatever is left).