By the end of 2010, Walden was entrenched at the back of the Angels' bullpen.
"At times, your talent might outplay a guy who has experience with limited or eroding talent," Angels manager Mike Scioscia said. "The bottom line is, who can do the role?"
Walden's potential never was in question, not with a fastball that can touch 100 mph. The Angels moved him to the bullpen this season, and he returned to Double-A Arkansas.
Walden, 22, posted a 3.35 ERA in 38 games there. The Angels jumped him to Triple-A Salt Lake for six games and then promoted him to Anaheim, 10 days before major league rosters expanded.
He had found his slider, and his command too. His first three appearances came in low-pressure situations, but after that the Angels only used him in games they won, or in games they lost by one run.
"That was very surprising," Walden said. "It still hasn't even sunk in that I'm here."
In his first 13 big league innings, Walden had a 2.03 ERA, 22 strikeouts and five walks.
The Angels traded closer Brian Fuentes, replacing him with setup man and former major league closer Fernando Rodney. The Angels have Rodney signed through next season, and he figures to open the season as the closer, but Scioscia was so intrigued by Walden's September performance that he would not downplay the notion that Walden might emerge as closer by the end of next season.
"He has more growth that we'd like to see, but it's a possibility," Scioscia said. "His presence, his confidence, his poise and his ability to repeat pitches have been a positive. You don't know how a guy is going to react (to the majors), but he's been impressive."
• The Angels called up Hank Conger, 22, their 2006 first-round pick. In his first major league start, Conger hit a two-run single and caught a two-hit shutout.
• The Angels' September callups also included first baseman/outfielder Mark Trumbo, shortstop Andrew Romine and righthander Bobby Cassevah.