SURPRISE, Ariz. -- Opening Day is just over a week away and the Reds still have not locked down who will comprise their five-man starting rotation. But it has come closer into focus.

“The roster decisions, the starting rotation, that’s working itself out,” Reds manager David Bell said on Tuesday morning. “It’s going to be soon -- I’ll be able to speak more accurately on that because we have to, but as of today, the way I feel about it is we’re just doing a good job of getting everybody ready.”

Here is what we do know:

• Tyler Mahle will be the Opening Day starter on April 7 vs. the Braves.
• Vladimir Gutierrez will be somewhere in the rotation based on his rookie year success.
• Luis Castillo and Mike Minor will both open the season on the injured list after each experienced shoulder soreness in the early days of camp. Bell hopes to have Castillo and Minor back some time during the month of April.
• Tony Santillan, who was competing for spots in either the rotation or bullpen, was told by Bell on Tuesday morning that he will open the regular season as a reliever.
• Graham Ashcraft, Cincinnati’s No. 8 prospect, was reassigned to the Minor League camp on Tuesday after competing for a spot.

From the spring roster, that leaves prospects Hunter Greene, Nick Lodolo and Reiver Sanmartin for the final three spots. Barring a surprise, they will all make the team. All three have enjoyed a nice camp. MLB Pipeline ranks Greene as the organization’s No. 1 prospect, with Lodolo at No. 2.

Here is more on all three pitchers:

Lodolo

Pitching three scoreless innings in relief vs. the Rangers during a 7-1 victory on Tuesday, Lodolo only added to his exemplary spring. In three games -- including two starts -- the lefty has a 1.23 ERA with one earned run and nine strikeouts over 7 1/3 innings.

Against Texas, Lodolo retired nine of his 10 batters, allowing only a two-out double by Nick Solak in the fourth inning. After his outing, he threw the equivalent of one more inning in the bullpen.

“I feel like I belong,” Lodolo said after the game. “I feel like my stuff is good enough. I believe in myself. I feel like every time out I’ve been facing pretty much everyone’s actual lineup, so it's definitely a confidence builder to go out there and just throw your stuff.”

On his final pitch of his outing, Lodolo froze lefty batter Nathaniel Lowe with a 94-mph fastball for a called third strike.

“Usually I feel like lefties sit on the big one from me,” Lodolo said. “It’s always on the back of their mind, especially with two strikes. That’s typically my put-away pitch, so you go there and go fastball and execute it, and it’s just like, ‘ooh.’”

Sanmartin

Sanmartin, 25, started Tuesday vs. the Rangers and delivered three innings with one unearned run, one hit and one strikeout. In two games -- including the one start -- he has a 0.00 ERA.

In the first inning vs. Texas, Sanmartin gave up a leadoff double but retired the rest of the side in order, getting Kole Calhoun on a called third strike to escape. A two-error play by third baseman Colin Moran to open the third inning led to a run. Throughout the game, Sanmartin was effectively using his changeup and slider to fool hitters into swinging.

“I knew I had it, and it was working really well. It was great today, knowing that I could use it a lot today,” Sanmartin said via translator Jorge Merlos.

Sanmartin was 2-0 with a 1.54 ERA in two big league starts -- both vs. the Pirates -- last season. The brief experience proved helpful this year.

“It really prepared me a lot for the season,” Sanmartin said. “Now you know when you’ve pitched two games in the Majors that you can’t mess up any pitches. Otherwise, they hit it out.”

Greene

In two games, with one start, Greene has three scoreless innings with five hits, no walks and three strikeouts. He is scheduled to start on Thursday vs. the White Sox.

During his previous start on Saturday vs. the Giants, Greene reached 102 mph multiple times, but impressed as well with the changeup he’s been developing. He even started two hitters with the pitch, something he hadn’t done previously.

After missing 2 ½ years with Tommy John surgery and the pandemic, Greene’s first full season didn’t come until he made 21 starts in 2021. Fourteen of them came at Triple-A Louisville. Because of a shoulder injury, Lodolo only made three starts for Louisville after he posted a 1.84 ERA in 10 starts for Double-A Chattanooga.

“They’re making a great impression,” Bell said of Lodolo and Greene after Tuesday’s game. “They’re pitching like they belong, and they do. It’s just about making sure it’s the right time.”