That's something that Doc has talked about doing, and I seem to recall a few back-to-backs last year where guys got the night off.
Has Lee played much small forward before? He seems to have decent size for the offguard, but not really for the forward position. Not a good rebounder. Looks like he played a TINY but of SF for Houston last year, but 90%+ of his playing time was at the 2-guard (and as per 82 games, he was not very effective - especially defensively - when he was in at SF).
The year before, he played essentially no small forward (1% of Houston's available minutes at the SF, versus 38% of their SG minutes).
In New Jersey ('09-'10), he got 54% of the SG minutes and only 3% of the SF minutes.
In Orlando his rookie year, again the substantial majority of his time was at SG (41% of the available 2-guard minutes, only 6% of the SF minutes).
I know the 82games figures aren't necessarily perfect, but their stats seem to back up my impressions of Lee; he's a shooting guard, pure and simple. He's played hardly any SF in the NBA, doesn't really have the size to do so, and last year was noticeably worse in the stints he did play there.
I'm not comfortable with Courtney Lee as the third string SF, not with Pierce (old) and Jeff Green (heart issue) being the only other SFs on the roster (you can't count on the rookie second rounder for any real contributions).
There are roster spots and at least a LITTLE money left to spend; they should acquire a depth SF, be it Pietrus (if no one else will pay him) or someone else.