Who's the #6 Starter?

Joe Kelly left yesterday's game with stiffness/soreness in his right arm.  He is not expected to miss any significant time.  But his injury brought up a question in my mind, namely who is the Sox #6 starter should one of the first 5 go down?  Is it Steven Wright?  Matt Barnes? Henry Owens? Brandon Workman?  Early on in the season, you would have to think that guys like Wright, Barnes & Workman would be primary choices simply due to previous big league experience.  If Barnes & Workman settle into bullpen rolls, then Wright becomes the #6 starter.  Barnes has been a starter his whole career, but the Sox like his velocity out of the pen.  Workman has had more success out of the pen & he is groomed to be a long man if needed.  If an injury occurs later in the season, I could see Owens edging Wright for a starting role.  That assumes that Owens continues to impress at the AAA level.  It's nice to have options & the Sox have 4 legitimate ones in Wright, Barnes, Workman & Owens.