"We're still evaluating," general manager Jon Daniels said. "We have a week or so to go. We haven't made any decisions."
Lincecum signed with the Rangers on March 7 and started the season on the disabled list because of a blister on his right middle finger. But that is no longer the issue.
The main issue is if Lincecum can regain enough of his former prowess to be an effective reliever at the big league level. The two-time National League Cy Young Award winner has not pitched in the Major Leagues since Aug. 5, 2016, with the Angels. He did not pitch at any level last year.
Lincecum has pitched in seven games with Round Rock and has a 8.31 ERA. In 8 1/3 innings, he has allowed 13 hits and six walks while striking out eight.
"The staff in Round Rock says it's getting better," Daniels said. "He's a little more comfortable and a little more consistent in the strike zone. The changeup has been his best swing-and-miss pitch. He has done a better job with his fastball getting ahead and setting it up."
Moore eyeing Tuesday return Left-hander Matt Moore, who is on the disabled list with a sore right knee, is shooting for Tuesday as the day he returns to the rotation. But the Rangers want to wait until after Moore throws a bullpen session on Saturday before making a final decision.
"He continues to progress," manager Jeff Banister said. "He'll have another bullpen session [on Saturday] and we'll see how he comes out of it."
Austin Bibens-Dirkx took Moore's spot on Thursday against the Royals and has not yet been sent to back to Round Rock. The Rangers aren't going to make a roster move until they are sure Moore can go on Tuesday.
Moore threw 70 pitches in a batting-practice session on Thursday and said it went well. Moore and pitching coach Doug Brocail have been working on his delivery, trying to keep him more balanced and straight down the mound toward home plate. Moore has had a tendency to open up too quickly and fall off toward the third-base side of the mound. That keeps him from getting maximum velocity on his fastball and sharp movement on his curveball.
"I think just being able to do the things we were trying to do more times than not was a positive," Moore said. "I think, in general, the implementation went well. I'm just trying be a little bit more balanced throughout."
Rangers beat • Ricardo Rodriguez is becoming an option for the Rangers' bullpen. He also started the season on the disabled list with right biceps tendinitis, but he has made 10 appearances in the Minor Leagues on a rehab assignment, allowing just one earned run in 9 2/3 innings. He is also eligible to come off the DL on Monday.
• Reliever Kevin Jepsen has refused outright assignment and is a free agent. He was designated for assignment on Monday after posting a 5.94 ERA in 21 games.
"I'm not sure if he's got something else lined up or just wants to look around," Daniels said. "He was great while he was here. Big-time pro, awesome guy."
• The Rangers acquired pitcher Michael Roth from the Cubs for cash considerations and assigned him to Round Rock. He was 1-2 with a 3.03 ERA in five starts and two relief appearances at Triple-A Iowa. He pitched in one game for the Rangers in 2016.