I was in this wonderful fantasy baseball league years ago. Great group of guys, and normally we drafted before the season began. That particular year, though, we drafted a few days after opening day (and yes, previous stats would count). One of the hottest commodities that year was a Cubs' outfielder named Karl "Tuffy" Rhodes. The reason was that Rhodes homered three times on opening day, guaranteeing to throw his price in our auction out of proportion because owners draft on hope and potential. He even hit one off Doc Gooden.
He also ended up with only 269 at-bats for the season, hit only eight home runs, hit .224 for his career and ended up in Japan. Every year, though, during our draft, his name would come up, more or less in "buyer beware."
That is not to say that Matt Davidson is not a good player, will not be a good player, and will not have a good season. It's just to say that after one game, it is hard to draw any conclusions at all, unless, of course, you are Dan LeBatard, the ESPN personality and Miami-area sports talk show host. LeBatard's reaction to Ian Happ's season-opening home run off the Marlins -- on the very first pitch of the MLB season -- is priceless.
The odds are that the Marlins will not be as awful at LeBatard suggests (they could be close, though) or that Davidson will hit 486 home runs (to Giancarlo Stanton's 324).
There remains a lot of baseball to be played.