T.R. Sullivan mentions today in the S-T that the Rangers aren't planning on calling up Frankie Francisco just yet.
After the awful Saturday outing in Corpus Christi, the Rangers are planning on having him pitch again for Frisco on Tuesday, and will re-evaluate the situation after that.
There's apparently some talk of optioning Francisco to the minors once his rehab stint is up, rather than activating him, since he has plenty of options left. That probably would be the best path to take, given where Francisco is right now.