DENVER -- Lefty reliever Phillip Diehl arrived at Spring Training confident his year would go as planned and he’d earn his first Major League activity. There was a twist along the way, but he was proven correct when the Rockies selected his contract from Triple-A Albuquerque on Monday.

Diehl, 24, stayed with his plan after a surprise trade from the Yankees. He had an impressive Major League camp (17 strikeouts in 10 innings) before the Yankees dealt him to the Rockies on March 23 for outfielder Mike Tauchman. Diehl, issued uniform No. 64, earned promotion to the Majors by posting a 2.30 combined ERA in 23 total games with Double-A Hartford (no earned runs in 11 appearances, covering 13 1/3 innings) and Triple-A Albuquerque (4.50 ERA in 12 games, 14 innings).

“I believe in myself,” Diehl said. “I had a great offseason. I had a good year last year. I know if I built upon that I would be given an opportunity to pitch with the Yankees. Now I’m a Rockie, and I’m ecstatic to be a Rockie and pitching in the big leagues.”

The Rockies selected Diehl and placed right-hander Seunghwan Oh (3-1, 9.33 ERA in 21 appearances) on the 10-day injured list (retroactive to Friday) with a left oblique strain.

Diehl arrives with a deceptive short-arm throwing motion, a low-90s fastball and a slider. While he doesn’t overpower hitters with velocity, he has been effective. Left-on-left, he has held hitters to a .107 batting average, while righties are averaging just .194. He has 279 strikeouts in 221 1/3 Minor League innings.

Diehl, in effect, replaces Chris Rusin, who was designated for assignment during the weekend after missing much of the season with a back injury and having a rough re-entry (four runs, five hits in one inning over two appearances). Diehl will join Jake McGee to double the number of lefties in a Rockies bullpen that has mostly performed well. Rockies relievers entered Monday third in the National League with a 3.92 ERA and a 13-5 record.

Because Diehl didn’t join the Rockies until the end of Spring Training, most of what the staff knows is from reports and video. Bullpen coach Darren Holmes said he looks to have deception from a delivery that somewhat resembles former Rockies closer Brian Fuentes.

“He can run it up there in the low 90s with a slider,” Holmes said. “He pitched above the zone pretty good and uses the slider below the zone. So far, on the Triple-A side, they’ve given good reviews.”

Anderson set for surgery

Lefty Tyler Anderson (0-3, 11.76 ERA in five starts) is scheduled to undergo surgery on Monday in Chicago to correct a chondral defect in his left knee, according to a report from The Athletic. Anderson has battled left knee soreness since the latter part of Spring Training.

It won't be clear until after the surgery whether Anderson will be able to return this season.

Freeland making progress in specific areas

Lefty Kyle Freeland, optioned to Albuquerque on May 31, is scheduled to make his second Triple-A start on Wednesday with the team off Tuesday. The numbers appeared more of the same in his initial Triple-A start last Thursday at Omaha -- four runs on nine hits (including a homer) in five innings of a loss. But through discussions, it appears Freeland made progress.

The Rockies wanted him to work on a curveball -- after he leaned on a fastball, cutter and slider for much of his career. The other key was increasing the difference in velocity between Freeland’s fastball and the changeup, and using the changeup with confidence. He did as assigned with both pitches, and the curve was especially effective.

So, while the statistics tell part of the story, the strategic improvements aspects and the work he’s doing on the two offspeed pitches are more important and are being watched closely from Denver.