PEORIA, Ariz. -- With absolutely no offense to Luke Gregerson, Mike Adams and closer Heath Bell, San Diego pitching coach Darren Balsley said Sunday that there's more to a successful bullpen than who pitches the final three innings of a game.

"Some of the most important guys in a bullpen are the middle men and the long men," Balsley said. "We've seen that here."

Gregerson, Adams and Bell, the Padres' two-time All-Star closer, got plenty in the way of notoriety -- especially for their successful body of work in shutting down foes for what was the best bullpen in the Major Leagues last season.

But with the offseason departures of Ryan Webb and Edward Mujica, who were traded to the Marlins in the November deal that landed outfielder Cameron Maybin, the Padres certainly realize you can't just slide anyone into that spot and hope for similar results.

So how does the rest of the bullpen look for 2011? It's mostly a fluid situation, as two of the Padres' top returning pitchers from last season -- left-hander Joe Thatcher and righty Ernesto Frieri -- have been sidelined with shoulder soreness.

Thatcher hasn't appeared in a game this spring, though Frieri will throw his second side session in three days on Sunday, and might be closing in on pitching in games.

Chad Qualls, who struggled mightily last season with Arizona and later Tampa Bay, is a lock to make the team and will likely fill that sixth-inning role -- or he could be used later in a game, if needed.

"I think he's going to have a good year," Padres manager Bud Black said of Qualls, who has impressed Balsley, as well.

"Qualls has been great," Balsley said. "He's been able to throw his sinker -- and it's tough to throw a sinker over here."

The Padres, at this point, are unclear who will fill the long-relief role that Mujica held last season. They would prefer that Wade LeBlanc win the No. 5 spot in the rotation, which would allow Dustin Moseley to pitch in long relief.

But Moseley, who is versatile enough to start or pitch in relief, has been impressive so far this spring. Moseley has a 2.08 ERA in three games, and has been good about pounding the strike zone.

If Moseley wins the fifth-starter spot, the Padres won't simply slide LeBlanc into the long role. He's a starter and will remain so -- no matter where he's pitching.

Veteran Randy Flores has looked good at times this spring, and has a 3.60 ERA over five appearances. If Thatcher is unable to start the season healthy, the Padres could decide to keep the left-handed Flores -- if they feel they need a lefty in the bullpen.

One player who has impressed in camp, but doesn't stand a good chance of making the 25-man Opening Day roster, is 25-year-old left-hander Colt Hynes -- who has struck out seven in 4 1/3 innings. He had a combined 2.10 ERA between two Minor League stops last season.

"He has been very impressive. He's a strike thrower who has some deceptions," Balsley said of Hynes.

There are still questions to be answered between now and when the Padres break camp on March 29, and fly to St. Louis. But Black feels the candidates to fill out the remainder of the bullpen are currently in the Padres' clubhouse.

"We have some guys we're very comfortable with from a depth standpoint," he said.