If you're in a 14 team league there aren't plenty of playable WRs. Definitely not a lot of high end WR2s.
As far as McCaffrey's ability to bounce back to 100 percent, I don't see the evidence that he will. Take a look at the injury analysis from 20 year orthopedic surgeon Dr. Jesse Morse. He wants no part of McCaffrey for the rest of the year. I definitely trust his opinion on ankle injuries over some of the angry value stuffers on this thread.
If you're in a league where you can absolutely fleece someone (like the guy posting above me just did with Zeke) by all means try to get some of that. In my leagues nobody is going to bite for that knowing that they get at best 5 or 6 weeks of low end RB1 production with the possibility of 3 or 4 weeks of low end RB2 production only after you're out of the playoff hunt. If you play in a 10-teamer, yeah maybe there's enough depth for everyone that you can afford to wait and see.
As far as RB value back is concerned, this is why you go with an RB robust strategy. Because you can always trade RBs for WRs, even injured ones.