Cole Tucker, the Pirates' top draft pick in 2014, had labrum surgery on his right shoulder in late August of 2015. Recovery time for the surgery was supposed to be close to twelve months, which would have kept him out all, or nearly all, of 2016.
Now, piratesprospects.com is reporting (sub. req'd) that Tucker has started making throws from shortstop and could return much sooner than anticipated. In fact, Tucker believes that he may return in April. Such an early return would be a huge improvement over Tucker missing a full season, especially since he was making rapid progress as one of the youngest players in full season ball; he had a .796 OPS in June and .798 in July. The quick recovery may also provide some early indication that Tucker will be able to stay at shortstop, which is not a given with this type of surgery. The P2 article notes that Tucker believes he hurt the shoulder in a first base collision in late May, which I suppose is better than the shoulder simply wearing out.
An early return for Tucker would leave the Pirates with a good sort of problem. Currently, the logical shortstop assignments would be 2015 first-rounder Kevin Newman at high A Bradenton and Adrian Valerio, the team's top 2013 international signee, at low A West Virginia. Tucker played well enough at West Virginia to earn a promotion, but the team could send him back there initially, with the possibility of a promotion once Newman earns a promotion to AA. That would force Valerio back to short season Morgantown. Valerio may be the best defensive infielder in the system, but his bat is well behind his glove, so another year in short season ball wouldn't be a disaster. Another option would be to send Tucker to Bradenton and move Newman up as soon as Tucker is ready to go. An added consideration could be the absence of anybody to play short at Altoona other than organizational-type players. If the Pirates share Keith Law's view of Newman to any degree, that's not an improbable move.