Casilla hit .336 with an .831 OPS during 31 regular-season games for Gigantes del Cibao, before hitting .397 with a .946 OPS in 17 playoff games.
"I'm tired of getting hits, bro," Casilla joked. "Oh my God. I was getting on base too much."
Casilla missed 57 of the Twins' final 58 games because of a strained right hamstring, but said it healed quickly during the offseason, which allowed him to get an early start in the DWL.
He said he faced Twins left-hander Francisco Liriano twice -- he had a bloop single and struck out -- and that Liriano looks like he's healthy. The numbers, though, haven't fully backed that up, as he has a 7.36 ERA in 11 innings pitched during the playoffs with Leones del Escogido.
Liriano, however, did allow just one unearned run over four innings with five strikeouts in his last outing on Tuesday.
"I talked to him when he was warming up, and I asked him how he was feeling, and he said 'way better,'" Casilla said. "So he's better. He threw a nice game the other day."