We haven't talked about Matt Joyce in a while.
Joyce's 13.6% walk rate is top five in the IL and his strikeout rate is around 24%. Overall Joyce has an .855 OPS. Per MinorLeagueSplits his platoon splits break down as such:
Versus LH: 107 AB, .252/.311/.486 (5 HR, 7 BB, 31 SO)
Versus RH: 284 AB, .282/.395/.482 (10 HR, 56 BB, 62 SO)
Joyce still kills righties. His approach facing them appears solid, walking almost as many times as he strikes out, showing some home run pop, and also hitting 23 doubles against the normal folk. Joyce isn't quite as comfortable with the alien species known as left-handers. He's not seeing a ton of them to begin with, but when he does he's struggling to reach base against them. The power is still there, just the familiarity with the strike zone and the ability to pick up pitches isn't.
Joyce's defense will always represent a good portion of Joyce's WAR, and TotalZone has him worth +11 runs in right field. I'm not sure what the correlation between TZ and UZR is, so take that figure with some salt. You have to figure he's a 5 < x < 15 defender in a corner at this point. Hopefully we can improve the precision on that range at some point in the next year or two. For what it's worth, the 2008 Fans Scouting Report ranked Joyce as an above average defender as well.
August has been kind to Joyce thus far and he's actually walked more than he struck out. With about 60 days needed in order to complete Joyce's first service year, he's appeared in 11 games this season and presumably has around 35-40 days left in that year, meaning the Rays will probably delay his September arrival until after the International League playoffs end. It's not like there's any rush for him to join this particular team anyways. Next year should be a different story.