We knew Josh Collmenter was going to be the Arizona Diamondbacks’ starting pitcher on Opening Night when they host the San Francisco Giants.

What we didn’t know, officially, was who would follow him. Now we do, albeit we are not sure of the order in which they will pitch.

Your 2015 #Dbacks starting rotation, in alphabetical order: Anderson

Cahill

Collmenter

De La Rosa

Hellickson pic.twitter.com/XK7wMH4s8v — Arizona Diamondbacks (@Dbacks) March 30, 2015

Chase Anderson, 27, started 21 games for the D-backs last season, going 9-7 with a 4.01 ERA. He struck out 105 in 114.1 innings while walking 40.

Trevor Cahill is entering his fourth season with the D-backs. Last year was his worst with the team — and as a pro — as his struggles led to a stint in the minor leagues as well as a role out of the bullpen. Overall, he posted a 3-12 record with a 5.61 ERA.

Rubby De La Rosa, 26, was acquired in the trade that sent Wade Miley to the Boston Red Sox. In 19 games last season — 18 starts — he posted a 4-8 record with a 4.43 ERA. He struck out 74 batters and walked 35 in 101.2 innings.

Jeremy Hellickson was added in a trade with the Tampa Bay Rays. The 27-year-old was the 2011 AL Rookie of the Year, but saw his numbers drop since that year. Last season, he was 1-5 with a 4.52 ERA in 13 starts.

Then of course there is Collmenter, the 29-year-old who was 11-9 with a 3.46 ERA last year.

Every pitcher in the rotation is right-handed. This announcement also means Daniel Hudson, who was vying for a rotation spot after coming back from consecutive Tommy John surgeries, will begin the season in the bullpen.

“It was a mutual decision,” @DHuddy41 on the decision to be in the bullpen this #Dbacks season. — Arizona Sports 98.7 (@AZSports) March 30, 2015

Follow @AZSports