MESA, Ariz. -- There were times last year when Cubs reliever Brandon Morrow felt he was finally turning the corner toward recovery. He would get on a mound at the team's complex, work through a series of pitches and sense the end of the comeback trail.

Then, reality would set in.

"I just couldn't pick up my cup of coffee the next day," Morrow said.

During a voluntary workout at the Cubs' Spring Training complex on Monday morning, the 35-year-old Morrow was among the many hurlers who had already arrived to camp. The right-hander -- back with Chicago as a non-roster invitee on a Minor League contract -- threw on flat ground one day after completing his fourth mound session of this latest comeback bid.

After missing all of last season due to arm woes, Morrow's schedule is more conservative than his mound neighbors in Mesa, Ariz. He is currently throwing off a mound every four days (one on, three off) and the Cubs will be closely monitoring the intensity of his workouts and how he recovers in the subsequent days.

In a perfect world, Morrow would be a part of the North Siders' Opening Day bullpen. That is his stated goal. Maybe looking through a more realistic lens, he proves himself in a Minor League setting at the front end of the regular season and impacts the Cubs' bullpen later in the summer. Really, either scenario would be a win for both sides, given the backdrop of the past two years.

"I'm not going to declare I'm back or anything like that, yet," said Morrow, whose last game appearance for the Cubs was on July 15, 2018. "But, I've been off the mound a few times and so far, so good. Cautiously optimistic."

? Cubs Spring Training FAQs, important dates

Morrow's last elbow/forearm procedure was on Sept. 3, when he underwent a radial nerve release and decompression surgery via Dr. Neal ElAttrache. He admitted to still experiencing some aches and pains, but the hope is it is all part of the ongoing rehab process. Morrow said the difference now is he feels fine while throwing and does not lose strength in the wake of any discomfort that flares.

"My motivation is just to get back and do it," Morrow said. "I felt like there was a lot of missed opportunity for me and the team. I felt like my absence created a lot of problems and problems the team had to address. But, we could be stronger for it this year."

Walker auditions for Cubs

Free-agent righty Taijuan Walker was in Cubs camp on Monday for an in-person mound workout in front of members of Chicago's front office and coaching staff. Following the throwing session, the pitcher respectfully declined an interview with reporters.

"Felt good," said Walker, as he exited the Cubs' complex.

The 27-year-old walker has been limited to 14 innings over the previous two seasons combined due to Tommy John surgery on his right elbow. Once a highly ranked prospect with the Mariners, Walker last put together a near-season's worth of work in 2017, when he had a 3.49 ERA with 146 strikeouts and 61 walks in 157 1/3 innings with the D-backs.

Worth noting

? The first four slots of the rotation belong to (in alphabetical order) Yu Darvish, Kyle Hendricks, Jon Lester and Jos¨¦ Quintana. In a chat with reporters on Monday, pitching coach Tommy Hottovy made it sound like Tyler Chatwood was in a great spot to claim the fifth job.

"He wants to be that guy," Hottovy said. "I think he's proven and given himself a lot of opportunities to be in that role. I think going in, in my eyes, he's kind of in that spot to be that guy. He's going to be on a starter program in Spring Training."

? Right-handers Alec Mills (out of Minor League options) and Colin Rea will also be in the mix for the fifth spot. Offseason addition Jharel Cotton will also be considered. Pitching prospect Adbert Alzolay, while also in that competition, might need more development time with Triple-A Iowa.

"We are all excited with what we saw him do when he came up last year," Hottovy said. "We have to be smart about, with him, just remembering the injury history. That was really his first healthy season in a while. So, we want to build off that and we want to continue his trajectory the way it is. There's no doubt in my mind he's going to be in the mix for stuff during this season."

? Victor Caratini caught 19 of Darvish's starts last season, and for good reason. With Caratini, Darvish had a 3.29 ERA and 9.7 strikeout-to-walk ratio. In the name of flexibility, Hottovy said the Cubs plan on making sure Darvish is paired more with Willson Contreras this spring.