I don’t know what to expect, and I don’t think anyone else does, either. Diaz, after two outstanding years of half-time play, was completely useless — worse than Francoeur — in 2008 before tearing up his knee on a fielding play. He made a couple of efforts to come back, but couldn’t.
In previous seasons, he had been somewhat better against lefties but didn’t have that dramatic of a platoon split. In 2008, he hit .319 .333 .420 against lefthanders and .167 .191 .182 against righthanders. It should be noted that even the rates against lefthanders are below average, and that he had essentially no secondary offense, making Francoeur look like Rob Deer. (His batting average was a few points above Francoeur’s, but Francoeur’s isolated power alone was higher than Diaz’s secondary average.) In previous seasons, Diaz had been batting-average-heavy, but had some power, a few walks, and would get hit by a pitch. Basically none of that was left in 2008, as his secondary average went from .202 and .215 in his first two years as a Brave to .111. You can’t survive as an outfielder with that little offense outside your batting average, and Diaz would have been hurting the team if he’d hit .300. It’s just that hitting .244, it was obvious.
So, what is Matt Diaz? A platoon player? A guy who got lucky, a guy who got unlucky, a guy who got both in succession? I don’t really know. I tend to think that he really is a .300 hitter and that he probably had an injury before the knee injury. I doubt he’s really good enough to slug .497, as he did in 2007, and thus he’s probably not good enough to play every day. I guess that makes him a platoon player.