© 2010 MLB Advanced Media, L.P. All rights reserved.

06/21/10 7:36 PM ET

Detwiler activated, sent to Double-A

WASHINGTON -- Left-hander Ross Detwiler was reinstated from the 60-day disabled list and optioned to Double-A Harrisburg, the Nationals announced Monday.

Detwiler, the Nationals' first-round pick in the 2007 First-Year Player Draft, had surgery in February to repair a labral tear in his right hip. He missed Spring Training and has not pitched for Washington this season.

He pitched for the first time in a rehab start on June 10 for Class A Advanced Potomac. He tossed three shutout innings with two strikeouts. In three rehab starts with Potomac and Double-A Harrisburg, Detwiler had a 0.84 ERA in 10 2/3 innings.

"He's going to need a little bit more time in the Minor Leagues," Nationals general manager Mike Rizzo said. "We want to see him get a little more arm strength and get his velocity up to where it needs to be for him to compete successfully up here. Once he's ready, we'll certainly consider him a guy to come up."

Guillen recalls lessons in return to DC

WASHINGTON -- Jose Guillen was back in Washington on Monday with fond memories of his two years with the Nationals.

"I got treated real well here. I had a great manager who really respected me, and I respected him: Mr. Frank Robinson," Guillen said.

"It was a great time. That was after I had the incident at Anaheim and came here, and a lot of people thought it was going to be the same. I got a really good manager who really played the game in the past and knew what baseball was all about."

Guillen was suspended for the last eight regular-season games of 2004, after a dispute with Angels manager Mike Scioscia, and was left off the postseason roster. Then, in November, the Angels traded him to the Montreal Expos, soon to move to Washington.

Some observers doubted Guillen could get along with the hard-nosed Robinson, but they meshed and remain close friends today.

"It was a great experience, something I'll never forget. A lot of the stuff I learned from Frank was great," Guillen said.

Robinson changed Guillen's approach to the game, including encouraging him to slide into second base more regularly.

"He said, 'I don't ever want to see you jog into a base. Go hard. If the second baseman stays in there, break both of his knees. That's the way you should be playing the game -- old school. You don't want to see a shortstop standing there,'" Guillen recalled.

"And in the past I used to get mad [when I was hit by a pitch], and wanted to charge the mound so many times. He took me to the side one time and told me, 'If you get hit, just go to first base and hope that a ground ball comes and you can tear into the second baseman and shortstop. That's how you get a payback.'"

There were other lessons during those 2005 and '06 seasons.

"He always told me, too, 'Don't ever argue with an umpire because as the batter, you're always going to lose.' I never do that, I never even look at the umpires," Guillen said.

"He was a great teacher. But you didn't mess with him, you went by his rules. He could get mean, too."

Mock moved to 60-day DL

WASHINGTON -- Right-hander Garrett Mock was moved from the 15-day DL to the 60-day DL, the Nationals announced Monday.

Mock, 27, has missed the last 65 games due to a right cervical disk injury. His only start for Washington this season was against the Mets on April 9, when he gave up two runs on four hits in 3 1/3 innings.

Nationals general manager Mike Rizzo said the move was a roster maintenance move.

"He's still rehabilitating from surgery, and we felt to get [Joel] Peralta up here, [Mock] was a likely candidate to go on the 60-day DL because of the neck surgery," Rizzo said. "He's not able to help us up here yet."

Greg Rosenstein is an associate reporter for MLB.com. Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.