Heading into this season White's minor league numbers were nothing spectacular, but good enough that he earned his way onto the major league roster of a stacked team like the Dodgers. He had a 3.70 ERA/3.87 FIP. He really struggled in AAA this year as he worked his way back from injury, but it appears as though he might have righted the ship upon his call up back to the majors.
Prior to being acquired by the Jays last season he pitched pretty well over the course of several stints with the Dodgers. He produced a 3.58 ERA/3.87 FIP. For a guy acquired primarily to be used as a swing man/6th starter these numbers are just fine. The results last season as a Blue Jay are admittedly ugly, but there are signs that suggest his ERA was inflated due to some pretty terrible luck on batted balls. He avoided barrels and kept the ball in the park, but despite an average exit velocity of only 87.8 MPH he surrendered a batting average on balls in play of .368. There is a massive gap between his ERA and FIP of nearly 4 full runs which further suggests the high ERA is something that may have normalized over time.
Frasso is a fun prospect to follow but he hasn't exactly been lighting AA on fire. This is his second season spending time in AA, and his total AA line shows a 4.41 ERA/3.13 FIP. He's experienced a lot of injuries over his young career and as such has a very high likelihood of ending up as a reliever. He's only averaged 3 innings per start in his AA time so it seems somewhat unlikely that he will be able to remain as a starter long term.
De Jesus is having a nice run of success in Vancouver right now. He's upped his season WRC+ to 120 after a few very good months at the plate. Over his last 49 games he's produced a 141 WRC+ including 9 home runs. He's starting to show why the front office was willing to ship out Frasso as part of the White trade.
White being used in low leverage situations doesn't take away from the fact that he's pitched well for the team so far. Low leverage relief has been a big weakness for this team, as key low leverage relievers such as Cimber and Phelps have either been hurt/ineffective or retired in the case of Phelps. Pop showed promise in this role before he eventually started to struggle and ending up on the injured list, so if White can be effective in this role he can eventually work his way out of mop-up innings and start pitching in closer games.