The Pittsburgh Pirates current rotation projects as following (with projections from Fangraphs)
Two other pitchers, as projected depth are Drew Hutchison and Jeff Locke. Hutch is projected at 47 innings started, 3.96 ERA, and a 3.88 FIP. Jeff Locke is projected at 56 innings started, with a 4.15 ERA and a 4.20 FIP.
The top three is a pretty solid top three, especially if Gerrit Cole’s arm can actually holds up, and which in that case, he will likely be better than his projection. But the back two spots is an area of need in terms of upgrading.