ARLINGTON -- The Rangers were able to reinforce their bullpen Sunday by activating right-hander Matt Bush off the disabled list. They are still on hold with right-hander Keone Kela, who is scheduled to throw another bullpen session Monday.
"He just needs more time," pitching coach Doug Brocail said.
Kela has been sidelined since Aug. 4 with a sore right shoulder. Monday will be his fourth bullpen session.
Bush had been out since his on-field collision with third baseman Joey Gallo on Aug. 20 against the White Sox. Bush suffered a concussion and a sprained right knee.

The knee was slow to respond, but his condition rapidly improved in the last week to the point where he is ready to pitch. He will wear a brace on the knee for security, but otherwise is good to go.
"It's go time, not sit back and wait," Bush said. "I feel good. I feel ready to go. I did everything I have to do to get back out there."
Bush gives the Rangers an experienced arm in the back of the bullpen. Texas has been relying heavily on rookie right-handers Ricardo Rodriguez, Jose Leclerc and Nick Gardewine since Bush and Kela have been out.
"This us allows use to use those power arms earlier," Banister said. "It allows us to use Rodriguez earlier, use Gardewine earlier, Tony Barnette."
Alex Claudio is still likely to be the closer, but Bush will be used in "high-leverage" situations.

"Just as we have been," Banister said. "We don't have time to massage him into the bullpen."
The Rangers did the same with Jake Diekman after he missed the first five months recovering from multiple surgeries to relieve ulcerative colitis.
"I'll be ready to do what Banister needs me to do," Bush said. "He is going to use whoever he thinks can do the job. I just need to be ready."
Bush just needs to remember he is no longer an infielder. He collided with Gallo chasing Nicky Delmonico's popup. Texas was in a drastic shift for the left-handed hitter, who hit a weak pop to a vacant area on the left side of the infield.
"My instincts took over," Bush said. "I was tired of giving up hits, tired of giving up walks. I saw that nobody was there."
The collision was frightening. Both players ended up in concussion protocol.
"I still have Gallo's nose and teeth in my temple," Bush said.