One constant theme during the Twins' four-year losing streak was the workload their bullpen was subjected to.

Now that they're winning, they're dealing with the same concerns.

Closer Glen Perkins made 15 apperances in May, while recording 13 saves. He was rested on Saturday and barely survived on Sunday. He's obviously tired, and there are four months of the season remaining.

Setup man Casey Fien has just returned from the disabled list. Blaine Boyer, a godsend, was seen icing his back earlier this week and has had to fill in for both Fien and Perkins.

The Twins' pitching staff has two current problems: Ricky Nolasco's ankle injury and the overwork of the key members of the bullpen. Both problems have easy solutions.

Whatever the tests on Nolasco's ankle reveal, the Twins should call up Tommy Milone from Class AAA, where he has an ERA of 0.70. If Nolasco couldn't get four outs on the ankle yesterday, he can't be trusted to pitch well in his next start. Shut him down and give Milone a tryout.

As for the bullpen, the Twins made a mistake when they sent down Michael Tonkin. He has the stuff to pitch at the end of games. Tim Stauffer does not have big-league stuff. Tonkin does. Tonkin may lack polish, but he'd be better in the big leagues, listening to Neil Allen and Eddie Guardado, then re-proving that he can get out minor-league hitters.

The big question around baseball is whether the Twins can sustain their success. I don't think they can keep winning in exactly the same manner, but they may not have to.

Their organizational depth should serve them well over the next four months. Milone, Tonkin, Jose Berrios, Byron Buxton, Ervin Santana, Miguel Sano, Kennys Vargas, Oswaldo Arcia and Josmil Pinto all could play roles. You could argue that the Twins, with the best record in the American League, could have a much stronger roster five weeks from now.

@Souhanstrib