If they are in contention into, say, August and Santana is one of their five best starters, IMO it's worth it. I don't believe they need to write off 2017. In fact, I hope they don't. I don't much believe in "rebuilding" when that means thinking you can build a team in 2016 for 2019.
So, by sacrifice bunting, if successful, you need a hit to get the tieing run across the plate. You'd need a hit somewhere to get the tieing run across the plate from first base, too. Only now, you have two chances instead of three to get that hit.