Well, I think you'll definitely miss Ludwick's bat. I believe he has a chance of coming back... supposedly, but with shoulder surgery, I would consider him done. Just look at your previous third baseman and former Cardinal Scott Rolen. When he started having shoulder issues, his power was absolutely gone... and he was never the same player again.
IMO, unless someone really grabs that position and takes it over, you're going to need a LF by the trade deadline.
Still, you'll be in the race for the division until the end. Though, it will be interesting to see how it impacts the entire NL Central without having the Astros.