DeJesus is out for an undetermined amount of time with a sore left ankle, and Gathright, the fourth outfielder, has taken over center field and the leadoff spot.
"It doesn't feel as bad as the other day," DeJesus said on Wednesday after returning from Kansas City. He underwent an MRI, additional X-rays and an examination by team physician Dr. Steve Joyce.
DeJesus admitted he was not ready to play immediately.
"Not yet. I just don't want this lingering all year," he said. "I just want to get it over with and then I don't have to worry about it the rest of the time."
Neither he or manager Trey Hillman believe a trip to the disabled list is likely right now.
"It's a slight sprain, but there's pain there, obviously," Hillman said. "If there wasn't, he'd be going. It's one of those things that there's irritation. We're going to go day-to-day. We don't think it's a DL situation right now."
Fortunately, he has Gathright, who took over for DeJesus in the third inning on Opening Day.
"Hopefully, Joey will add on to what was a great Spring Training for him and he can carry that into a few games played here and let David get a little extra rest and healed up good," Hillman said.
Gathright, a left-handed batter like DeJesus, had a .349 average in the Cactus League.
"It was a good spring," Gathright said. "I worked hard. It paid off. Hopefully it will continue to work out this year."
His terrific speed certainly paid off in Arizona, where he stole 12 bases in 12 attempts. That compares to nine steals in 17 tries last season. Now there's progress.
Gathright credits first-base coach Rusty Kuntz with adding to his base-stealing knowledge.
"I've learned a lot over the years, but this Spring Training, I learned a lot of things from Rusty that I had no idea about," he said. "It's a process and I'm hoping it works out. Rusty taught us w-a-y too much right away. But we got it, I think we learned a lot this spring, and it's going to help us this season."
Gathright also improved his knack of bunting for base hits. This spring, he had the odd habit of popping a bunt over the pitcher's head for a hit.
"I don't know how that happens. It happened like five times in this spring. Maybe more than that. I'll take 'em anytime I can get them, though," he said. "It's a hit in the books. I don't try to do it, but it keeps happening."
What he's actually trying to do is push the ball on the ground past the pitcher and toward the second baseman.
In the outfield, Gathright believes he's polishing his skills as well.
"Outfield is outfield," he said. "You're either going to take good routes or bad routes. You don't know what's going to happen from day to day. I think I've improved a lot in the outfield."
Just prior to Monday's opener, Gathright was musing about being the fourth outfielder, a guy on the bench.
"I play to start," he said. "It's not up to me whether I start or not. All I can do is go out and play my game. Whenever it's my time to be in the field, I'm going to go out and be ready. If it's time for me to be a starter, wherever, I'm just going to keep what I'm doing -- keep learning as much as I can and play hard."
Little did Gathright know that DeJesus would aggravate his ankle injury in the second inning that day, and that Gathright would be in the lineup in his stead.
And he might be there for a few days. Hillman will approach using DeJesus with great caution, not wanting to risk a long layoff. The next series will be at Minnesota, where there's an artificial turf that is hard even on healthy legs.
"I can't say he's not going to play there, but we'll be cautious if he does," Hillman said.
Either way, Gathright is primed to go.
"If I'm in the lineup, I'm ready. If not, I'm ready to back up or go in whenever they need me," he said.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.