With Kevin Hart's struggles this spring resulting in the plan to have Dan McCutchen start today's now-rained out Grapefruit League game against the Rays (McCutchen will now start a minor league game tomorrow as well to keep the rest of the rotation on schedule) and Kevin Hart starting tomorrow's Triple-A game at Pirate City, it's pretty obvious that the team is starting to hedge their bets with their earlier statements about Hart more or less having the fifth starter's job locked up. That's logical; spring training stats don't mean much, but when a guy walks 13 hitters in 4 2/3 innings it's damn near impossible to ignore it.
Still, the team obviously has a very high opinion of Hart and they think that his struggles are based on inconsistencies in his delivery and a difficulty carrying his bullpen work to the mound. This means that despite what most fans seem to think, this competition is not at all over. A good start by Hart tomorrow would likely earn him another chance in a Grapefruit League game and a good start there would probably put him back into the lead for the final rotation spot. Frankly, it probably doesn't matter at all what McCutchen does in his start today with the Pirates. The competition is completely dependent on Hart. The Pirates don't care what Hart's final line is in Florida, only that he proves he can throw strikes consistently.
This is obviously far from a sure thing, but we know that Joe Kerrigan has already been doing a lot of work with Hart. Using Joe Lefkowitz's PitchFX tool, I compared Hart's release points with the Cubs at Wrigley Field to his release points with the Pirates at PNC Park (the usual sidebar exists here: each park's PitchFX cams are positioned slightly differently and I didn't want to compare across parks, which is why I only used his home parks). The sample size for the Pirates is pretty small and since Wrigley and PNC are obviously different parks the comparison shouldn't be viewed as 1:1, but it certainly looks like the Pirate cluster is tighter than the Cub cluster. That matches pretty well with the idea that Kerrigan is trying to make Hart's delivery more consistent.
There are, of course, the questions of why the team so obviously prefers Hart and I guess some won't be satisfied with the answer that his stuff is better and thus his ceiling's higher, but it really is true. I know I've pointed to this FanGraphs post about Hart before, but I'll do it again for the sake of this discussion. Stripping away balls and strikes, Hart gets more hitters to chase pitches out of the strike zone (using FanGraphs and said post by RJ Anderson as a guide, he gets hitters to swing at 28.8% of pitches out of the zone for his career vs. 23.1% for McCutchen in his short stint with the Pirates last year) and to swing and miss at those pitches (hitter's make contact with 58% of those out-of-zone pitches that they offer with against Hart, vs. 63.9% against McCutchen), which boiled down to plain language means that he's harder to hit than McCutchen is (granted, in a much smaller sample size for McCutchen, but since we're already working with the hypothesis that Hart has better stuff than McCutchen we'll let this numbers be a loose confirmation of that).
If the Pirates were actually competing for something this year, they might be more inclined to force Hart to prove he's found his command in Triple-A while using McCutchen to limit damages in the fifth starter spot, but what they're really interested in is finding guys who can be more than rotation-filler for a longer period of time. Since Hart's stuff is good (probably better than both lefties in the rotation and maybe better than Ohlendorf as well, depending on who you think the real Ross Ohlendorf is) I think they're probably inclined to give him a decent-length look in Pittsburgh this year if he shows them even a flash of something before spring training ends.