"The Phillies just got better," Nats general manager Mike Rizzo told MLB.com in a Monday telephone interview. "He's a great pitcher. We respect them, and it's going to be fun to compete against them this year."
Sources say Washington explored the possibility of signing Arrieta in recent months. When asked to comment on how advanced the talks were between the Nationals and Arrieta's agent, Scott Boras, Rizzo replied: "He's a Phillie now. I'm not going to discuss what might've been or could've been. The Phillies just signed a great competitor."
Rizzo downplayed the possibility of any signings for the Nationals between now and Opening Day, saying, "We like the team we have. We're getting prepared to open up in Cincinnati. That's our goal."
All of which means that Cole, 26, is likely to begin the season as the Nats' No. 5 starter. He was supposed to start against the Tigers here in Monday's game, a 5-4 Nationals win, but he was scratched due to an illness. Cole has a 5.40 ERA in two Grapefruit League starts.
"We're still in competition for some [roster] spots," Rizzo said. "With the fifth-starter spot, A.J. is in the lead. He's out of [Minor League] options. His stuff is good enough [that] he'll make the team somewhere. We feel he's got the best chance of getting the fifth starter's spot, but [Erick] Fedde has thrown extremely well this spring. He's back up to 96, 97 mph with his fastball. We have good depth there."
Rizzo mentioned right-hander Edwin Jackson and left-hander Tommy Milone -- non-roster invitees to Major League camp -- as additional candidates to provide rotation depth during the season.
Jackson started in place of Cole on Monday, with mixed results. Jackson relied on an electric breaking ball to retire six of the first seven Tigers he faced, but he began his third and final inning with a walk, double, walk and single. The Tigers, though, scored only once against him.
"Wasn't bad," Jackson said of his outing. "Smooth sailing, pounding the strike zone, then a leadoff walk. I can definitely do a better job on that. But all in all, it was great."
At this time last year, Jackson was unsigned and throwing bullpen sessions at home in Arizona. He joined the Orioles on a Minor League contract in April and returned to the Majors with Baltimore -- his 12th Major League team, one behind Octavio Dotel's all-time record. Jackson finished the season with the Nationals, for whom he'd pitched in 2012.
Asked if he'd have interest in passing Dotel -- a former Cardinals teammate -- to claim the record for himself, Jackson grinned and said, "Lucky No. 13? Not right now, because I'd rather be here."
Nationals manager Dave Martinez praised Jackson's attitude and versatility before Monday's game, saying he's being evaluated as a possible long reliever as well as a starter.
"My standpoint is to go out and put the pressure on the team to make the decision," Jackson said. "It's easy to get caught up in roles, what spots are left in the rotation. The only thing I'm focused on [is] to pitch like I know I can and put pressure on the organization to want to make a move.
"I feel like I'm wanted here. For me, it's just going out and doing it. I'm not necessarily trying to prove anything to anyone. They know what I can do. They know what I can't do. I just want to progressively get better, get more consistent, have fun and help the team win. I know we've got a special team here."
The Nationals will owe Jackson a $100,000 retention bonus if he's still on a Minor League contract five days before the regular season begins. His one-year contract has a $1.5 million salary in the Major Leagues. The deal also includes a June 1 opt-out clause, which Jackson hopes is irrelevant, because that would mean he'd be back in the Majors before then.