ANAHEIM -- When the Angels made the move to acquire two-time Cy Young Award winner Tim Lincecum, it was out of necessity.
Injuries have plagued the Angels throughout this season, particularly in their starting rotation. As some pitchers are priming to make their returns, though, the once-thin rotation could require some cuts.
Lincecum has struggled since picking up a win and tossing six one-run innings in his season debut in Oakland on June 18. His last start, in Baltimore on Sunday, was perhaps his best since that promising opener. He lasted 5 2/3 innings and gave up three runs on nine hits, taking the loss. His velocity remains in the high 80s and his mechanics and command still haven't fully clicked in his return from offseason hip surgery.
With left-handers Tyler Skaggs and Nate Smith looming in the Minors, Angels manager Mike Scioscia was unable to guarantee that Lincecum would remain in the starting rotation for the rest of the season.
"I think for any player on a Major League field, it's performance-based," Scioscia said. "He needs to perform well, and nobody is immune to that. We have a lot of confidence that [Tim] is going to do what he needs to to be one of those five guys who are going to give us a chance to win games as a starting pitcher."
Lincecum is a free agent this season after signing a one-year, incentive-laden deal hoping to rebuild his value.

Skaggs is 23 months removed from his last Major League start after undergoing Tommy John surgery in August 2014 and dealing with various setbacks. At 25 years old, he remains one of the top young pieces in the organization and has made consecutive five-inning outings at Triple-A Salt Lake. Skaggs is slated to start again Thursday night and could be knocking on the door of the big leagues by the end of the month.
"Right now, Tyler's looking at performance," Scioscia said. "It's about how effective he can be, his pitch efficiency and trying to get to a certain point in the game and pitching well. We all feel he's close, but he just needs to refine his pitches and get where he needs to be."
Smith, who has posted a 3.07 ERA in his last seven Triple-A starts, was the Angels' lone representative in Sunday's SiriusXM All-Star Futures Game and is the club's top pitching prospect according to MLBPipeline.com. Scioscia said the 24-year-old Smith has impressed and that he's on the club's radar for future callups.
Worth noting
• Angels outfielder Craig Gentry has started his rehab assignment with Class A Advanced Inland Empire, though Scioscia said he's still not close to making a Major League return. He was originally diagnosed with a right lumbar spine strain and was near a return last month before being set back with a personal medical condition. Gentry hasn't played since April 25.
• The Angels added international prospect Andersson Espinal, the club announced Wednesday. He is a left-handed pitcher from the Dominican Republic.
• C.J. Cron underwent surgery on Tuesday to repair a left hand fracture. Scioscia said the surgery went "very well," and he hopes to keep him on the 4-6-week timetable.
• C.J. Wilson's season-ending shoulder surgery is scheduled for Friday. The surgery will fix the fraying of his labrum.