Lowe pitched 4.1 innings for the Indians over the last 10 days, somehow only being charged with one run, despite allowing 5 hits and issuing 5 walks (errors and unearned runs are the secret to his ERA's success). Him being sent back down is no surprise.
Hagadone, a 28-year-old lefty, was Boston's 1st-round pick in 2007, and came over to the Tribe as part of the Victor Martinez/Justin Masterson trade. He's thrown a few innings of relief for the Indians in each of the last three seasons, but has never stuck in MLB, due in large part to his 5.59 walks per 9 innings (8th worst among 535 pitchers with 60+ innings during that time).
He's thrown 23.1 innings for Columbus so far this season, with a 3.09 ERA, an impressive 13.50 K/9, and a more palatable 3.47 BB/9. His fastball sits at 94 MPH or so, and he's got a slider he throws in the low 80s. Those pitches from a southpaw make him a potentially valuable bullpen weapon, but the results have not yet matched his stuff. Hopefully that changes this time around, and he becomes a valuable member of the team.