Prospect Nate Eovaldi to start

PHOENIX -- As expected, the Los Angeles Dodgers plan to purchase the contract of highly touted right-hander Nate Eovaldi from Double-A Chattanooga sometime before Saturday night's game against the Arizona Diamondbacks at Chase Field, when he will make his major league debut.

The team announced the move after Friday night's game 7-4 victory over the Diamondbacks, adding that right-hander John Ely was optioned to Triple-A Albuquerque to clear a roster spot. The Dodgers presently have two open spots on their 40-man roster, so no corresponding move will be needed there.

Eovaldi will take the rotation spot of rookie Rubby De La Rosa, who has been lost for the remainder of this season and most of next season because of Tommy John reconstructive surgery on his right elbow, which will take place next week. Eovaldi is 6-5 with a 2.62 ERA in 19 starts and one relief appearance this season for the Lookouts, and he has allowed just 76 hits in 103 innings.

"We have been talking about (Eovaldi) all along,'' Dodgers manager Don Mattingly said in announcing the move. "He was going to be up here at some point, maybe in September. With Rubby going down, it gives us a chance to let him throw a few games and see where we're at with him and what it looks like.''

Eovaldi, 21, was the Dodgers' 11th-round pick in the 2008 amateur draft and likely would have gone higher if not for the fact he had committed to Texas A&M University and was thought at the time to have signability issues. He also underwent Tommy John surgery in high school, costing him most of his junior season, but he came back as a senior.

Although he wasn't invited to major league spring training, he did pitch in three Cactus League games for the Dodgers this year, including a perfect ninth inning and a save against the Chicago White Sox on Feb. 28.

Eovaldi attended the same high school (Alvin, Texas) as Nolan Ryan.

Tony Jackson covers the Dodgers for ESPNLosAngeles.com