"At first, obviously I was frustrated, but I knew I had to learn different things to get back into who I was as a player, especially with my hitting -- getting my control and making good swings at good pitches," Rosario said through an interpreter.
Rosario had previously been passed over for promotion twice, with the Twins electing to recall outfielders Byron Buxton and Max Kepler in order to give Rosario more time to focus on making contact with the ball and having fun while on the field.
As a result, Rosario says he returns to the Twins a much more confident hitter.
"I felt confident in the way I was hitting the ball -- I was making more contact," Rosario said. "When you're having more contact, it's easier to lay off those bad pitches. I think that was the key for me down there."
The timing of the corresponding move to designate Jepsen came as a slight surprise, especially in light of shortstop Eduardo Escobar's hamstring strain suffered in Saturday's game and manager Paul Molitor's voiced desire to stay with a 13-man pitching staff.
However, the designation itself didn't come as much of a surprise, as Jepsen had struggled to a 6.16 ERA and a .333 opponents' batting average in 33 appearances this season.
"This is a first for me," Jepsen said. "Sometimes, a change in scenery kick-starts stuff. I feel great -- I just need to get back on a roll. I've always done well in the second part of the season, so the confidence is there. I'm going to be fine. It's just a bump in the road."
Jepsen was one of the strongest arms out of Minnesota's bullpen during last season's playoff push, when he recorded a 1.61 ERA with 25 strikeouts and seven walks in 28 innings after being acquired from the Rays.
He took over for Glen Perkins as the team's interim closer this season but was removed from the position in early June after allowing runs in 12 of his 25 appearances.
Although Escobar avoided the DL for the time being after his on-field evaluation prior to Sunday's game, he might not yet be in the clear. Right-hander Trevor May completed his rehab assignment with Rochester on Saturday and returned to the team on Sunday.
• Third baseman Trevor Plouffe was scratched from Sunday's lineup with sore ribs. Molitor said the injury has been getting worse in recent days, so he'll be re-evaluated on Monday. There's a chance he could land on the 15-day disabled list to make room for May, who is expected to be activated on Monday.