The Pirates have promoted Andrew Lambo and optioned Gerrit Cole to Bristol. Cole isn't going to pitch for Bristol, obviously; he'll be back in a couple days when rosters expand. Bristol's season ends today, so the Bucs will just be able to promote him again for his next start -- no harm, no foul.
Pedro Alvarez and Travis Snider are both dealing with what appear to be minor injuries, so the Pirates are a bit short on corner types and left-handed hitters. As fill-ins go, Lambo is a very good one. The Pirates have never seemed overly interested in him, but it's unusual that a team can dip as far into the depth chart as the Bucs are dipping now and come up with a guy with a good prospect pedigree and two straight years of Triple-A OPSes of .933 or higher.
Anyway, as long as Snider and Alvarez's injuries aren't serious, Lambo isn't going to get a ton of playing time, and he's only coming up two days before the rosters would have expanded anyway, so we shouldn't read too far into this. In the meantime, though, it's nice to have another power source around.