Eflin was optioned to Triple-A Lehigh Valley following Sunday's loss to the Reds.
Eflin was torched at home by the Reds to the tune of seven earned runs on nine hits -- including four long balls -- over five innings Sunday. Considering the 23-year-old is now 0-3 with a bloated 6.13 ERA and 11 homers allowed in 47 innings (eight starts), the team has decided to send him down to get his game straightened out. Eflin's replacement in the rotation has not yet been announced.