WASHINGTON -- Before Thursday's game against the Phillies, Nationals pitching coach Steve McCatty said he wasn't happy that his staff walked 17 in the first two games of the season.

McCatty declined to give excuses as to why the staff hasn't been able to throw strikes, but it's obvious that the pitchers haven't been aggressive when facing Phillies hitters such as Chase Utley, Jimmy Rollins and Raul Ibanez, who had a combined 10 walks entering Thursday's action.

"We have to be more aggressive, pound the strike zone, and we haven't done it," McCatty said. "You can't sit there and say it's mechanical. We are playing a pretty tough team. There are a lot of times, the mental part of a pitcher is, 'These guys can hit.' They try to make too good of a pitch, you get behind in the count and you walk guys instead of saying, 'Here it is. I'm just going to make a good pitch and make them put the bat on the ball.'

"I don't know if the mental part has entered into it or not. It's not an excuse. We have to be better than that. We have to throw strikes and make them hit the ball."

McCatty talked to the staff before Thursday's game. Whatever he said, it worked as the Nationals walked only three in a 6-5 victory over the Phillies.

Morse day-to-day with sore left calf

WASHINGTON -- Nationals outfielder Mike Morse said his left calf is still sore and he ruled out being placed on the disabled list. Manager Jim Riggleman indicated that Morse will be used only in an emergency situation.

Morse suffered the injury while catching a sacrifice fly by the Phils' Raul Ibanez in the seventh inning Wednesday. Morse tried to stay in the game, but the pain grew worse and he was replaced in right by Cristian Guzman in the top of the eighth inning. Morse is expected to miss a game or two.

"It feels like a little bruise," Morse said. "I'm not worried about it. If [the trainers] are not worried about it, I'm not worried about it. I can walk on it."

Walker impressive in first Nats appearance

WASHINGTON -- Right-hander Tyler Walker made his Nationals debut Wednesday and was easily the team's best pitcher that day, throwing two scoreless innings, while striking out three.

The ironic twist is that he was successful against the Phillies, the team he played with last year. Walker appeared in 32 games for Philadelphia and had a respectable 3.06 ERA in 2009, but was left off the postseason roster. Walker became a free agent and signed with the Nationals in late January.

Walker will receive his National League pennant-winning ring from the Phillies during the middle of April.

"The name of the game is throwing strikes," Walker said. "You have to get ahead of these hitters. They are the best hitters in the world. You have to get ahead, strike one. The batting average goes down dramatically if you get ahead of these guys.

"It helps to see them a little bit, but it all comes down to execution. The flip side is, they know what I'm going to throw, too. So if I execute my pitches, they are not going to get on base. It's over with now and you get ready for Thursday."

Nats try to find way to cool off Howard

WASHINGTON -- The Nationals insist that Ryan Howard has holes in his swing, but entering Thursday's action, Howard was 4-for-11 with two home runs and five RBIs.

Nats reliever Tyler Walker, a former teammate of Howard's, has an idea how to get the left-handed hitter out.

"You can't get into any particular pattern with him," Walker said. "He goes in stages of being ultra hot. When he's hot, there are not many holes in his swing. When he is not going well, you take advantage.

"It comes down to execution of pitches. If he hits a good pitch, tip your hat. If it's a bad pitch, you have to make the adjustment and the correction. I don't think he is hitting great pitches. He is hitting bad ones."

Howard didn't hit any home runs Thursday, but he went 2-for-4 with an RBI. For the series, Howard went 6-for-15 with two home runs and six RBIs.