"On and off," Washington said. "He has some good days and has not-so-good days. I guess you could say he's a little inconsistent."
The two left-handers had distinctly different outings on Sunday in the Rangers' 6-5 loss to the Angels. Ross pitched two scoreless innings. Kirkman allowed four runs in the eighth and ninth innings, as the Angels rallied.
"Today, he wasn't very good," Washington said. "He left too many balls up."
Kirkman was once the favorite to be the Rangers' left-handed reliever. He no longer holds that distinction. Ross has come to camp as a long shot and taken it away.
"It's obvious the kid is doing well," Washington said.
Ross, after two scoreless innings against the Angels' best hitters, has yet to give up a run in six official Cactus League appearances, although he allowed four runs over 2 1/3 innings in a start against the Brewers that was eventually rained out. The Rangers have been willing to overlook that one rough outing because all others have been impeccable.
"He has been very impressive," Washington said. "If you were going to have a frame for pitching, it would be work fast, throw strikes and get outs. That's what he does."
Ross was the Rangers' second-round pick out of high school in 2008, and he has pitched just six games at the Double-A level. He has also been a starting pitcher all through the Minor Leagues. But the Rangers have never been afraid to push young pitchers, and club officials said they are comfortable breaking Ross into the big leagues by using him out of the bullpen.
The Rangers have three spots open in a seven-man bullpen that already includes right-handers Joe Nathan, Mike Adams, Alexi Ogando and Scott Feldman. Mark Lowe likely has the fifth spot wrapped up, and the Rangers seem determined to take Koji Uehara even though he has a 14.21 ERA, while opponents are hitting .357 off him.
The seventh spot could go to either right-hander Yoshinori Tateyama or one of the left-handers. The Rangers want that left-hander to get right-handed hitters out, as Ross did on Sunday when right-handed hitters were 1-for-4 against him.
"So far, it doesn't matter who is up there, he throws strikes," Washington said. "He works fast, throws strikes and gets outs."
Ross retired the side in order in the third. He started the fourth by getting Albert Pujols on a fly ball to left before Torii Hunter singled and Vernon Wells walked. But Ross, in a lefty-on-lefty matchup, got Bobby Abreu to hit into an inning-ending double play.
"It was awesome," Ross said. "I've never faced hitters like that before. It was cool."
Tateyama also threw a scoreless inning, has a 1.29 ERA for the spring and opponents are hitting .192 off him. He could force the Rangers to go to an all-right-handed bullpen or push aside Uehara.
"He has been really good," Washington said. "Tateyama has been good from day one, hitting his spots, changing speeds, doing things quickly."
The Rangers will keep looking at Ross. They want him to pitch back-to-back games this week, which is a prerequisite for any reliever trying to make a Major League team. Ross has a serious chance to make this team.
"I'm just enjoying this," Ross said. "I came in here not expecting anything. If it doesn't happen, it doesn't happen. If it does, it will be an unbelievable thing."