It's not a sure thing, but I still think it will happen. There may be rumors right up until draft day that the shoulder issue will scare the Pirates off, but in the end I think Rendon is the best overall hitter in the draft and I think the Pirates will agree.
Rendon was widely regarded as the top overall talent in the draft until his stock dropped due to a series of injuries. No one has really stepped up in his place, though, and I think the Pirates probably ought to pick an excellent college hitter who still has plenty of upside, as opposed to a polished lefty pitcher like Virginia's Danny Hultzen, a high-upside college hurler who's had his ups and downs like UCLA's Gerrit Cole, a high-school pitcher like Dylan Bundy, or a toolsy but raw high-school hitter like Bubba Starling.
Speaking of those players, Sickels has Cole going to the Mariners at No. 2, Hultzen going to the Diamondbacks at No. 3, Bundy going to the Orioles at No. 4 and Georgia Tech pitcher Jed Bradley to the Royals at No. 5. The Pirates and Mariners are both still wild cards, so it's hard to predict what the other teams will do, but Hultzen to the Diamondbacks and Bundy to the Orioles both seem pretty likely.
Sickels has Starling falling to the Cubs at No. 9. I find it hard to believe that a tools-obsessed Royals organization would pass on the toolsiest player in the draft, particularly given that Starling is from Kansas. But Sickels, who is also from Kansas, probably has a better idea of that sort of thing than I do.
Other interesting picks here include Kentucky pitcher Alex Meyer to the Diamondbacks at No. 7 (yes, they have two picks in the first round) and high school shortstop Francisco Lindor to the Angels at No. 17. I think that's the highest I've seen Meyer, but he's been climbing draft boards recently. As for Lindor, I'd be very surprised if the top shortstop in the draft lasted that long.