With no official word yet from the Padres on Robbie Erlin being called up there obviously is also no word on what his role might be. But since sources and sources of sources and brothers of sources' sources are reporting the call up is real, we can speculate based on what the team needs right now.
The team is getting shellacked these last 5 games and the pitching staff is getting overextended. Times were already tough before Tyson Ross suffered a shoulder injury, but since then things have cascaded. The team was already eyeing what to do for Ross' next start when Clayton Richard got ill and forced long reliever Andrew Cashner into the starting rotation. Cashner pitched for about as long as you could expect a long reliever would on short notice, but the bullpen needed to pick up some extra innings. Two days later, Jason Marquis just didn't have his stuff and Anthony Bass picked up 3 1/3 innings. Clayton Richard returned to the rotation the day after and could only muster 1 1/2 innings forcing the Padres' newly promoted secondary long reliever, Thad Weber, to go 4 1/3 innings. Which brings us to today. Edinson Volquez is scheduled to start tonight against the Milwaukee Brewers. He is averaging less than 5 innings per start this year. There is a good chance the bullpen will be needed.
So with all that information about the current pitching situation, where does that leave young Robbie Erlin? My initial guess is that he is replacing poor Thad Weber in the bullpen and will be a long man, at least for today. Another option is that Andrew Cashner will not make a start on Friday like Buddy Black claimed yesterday, but instead Erlin will start Friday and Cashner will be available in long relief beginning today. A third option could be a temporary 6 man rotation where Erlin will get a spot start in the next few days and no one gets demoted out of the rotation. That option does not solve the problem of what to do if Volquez can't go more than 5 or 6 innings today.
The one option I left out is Erlin replacing one of the non-Cashner pieces permanently in the rotation. I do not see that happening unless someone has a yet unreported injury. Volquez and Richard have been bad, but I just can not see either moving to the bullpen or getting dumped at this point (especially Richard). Marquis and Stults have not been bad enough to warrant replacement. On top of that, a permanent placement in the rotation this early in the season could potentially force Erlin to accumulate a lot more innings this season that the club would like. A spot start or a long reliever would not lead to that outcome.
Personally, I would like to see Erlin work in the bullpen for a bit. Partially for selfish reasons since I will be attending tonight's game and would like to see the young southpaw's debut. He would follow in the footsteps of Tim Stauffer, Cory Luebke, Anthony Bass and Andrew Cashner who all started out their major league careers in the bullpen before moving to the rotation. Of course, all of those pitchers missed significant time in 2012. So, maybe there is something to cautious about when considering that route.