ST. LOUIS -- Cubs manager David Ross knows that Jake Arrieta would rather be in the rotation right now than hitting a mental reset button while on the injured list. Ross also thinks the break has been good for the right-hander.

"It's had to help," Ross said prior to Tuesday's game against the Cardinals at Busch Stadium. "Especially for a veteran guy, a break in the middle of the season to reassess, when you're not performing the way you want to, isn't a bad thing."

There is no established timetable for Arrieta's activation from the 10-day IL after a bout with right hamstring tightness, but Ross noted that the righty is making progress. Arrieta is slated to throw a bullpen session within the next few days.

Ross added that the 35-year-old Arrieta -- shelved on July 7 -- threw off a mound during the Cubs' recent trip to Arizona with no issues. The manager said righty Kyle Hendricks watched his teammate's workout and reported good things.

"He said [Arrieta] had some really nice movement to his stuff," said Ross, who was unsure as of Tuesday whether a Minor League rehab assignment would be in Arrieta's comeback program.

In the meantime, Arrieta will keep searching for solutions to his issues on the mound. In his last start on July 6, the righty surrendered seven runs in 1 2/3 innings against the Phillies. Arrieta has a 10.41 ERA in his last seven turns (23 1/3 innings), and an 8.55 ERA with a 1.005 opponents' OPS in his last 12 outings (46 1/3).

Ross said he didn't "want to speak for" Arrieta, but noted that he recalls his own IL stint in 2016 that helped him.

"It was nice to have a mental break for me," Ross said. "... A little bit of a break in the middle never hurt the body and mind."

Ross to Lester: 'Nice homer'
Yes, Ross caught wind of the fact that former Cubs lefty Jon Lester launched a home run for the Nationals in an 18-1 rout over the Marlins on Monday night. And, of course, the manager sent his old batterymate a message.

"I texted him. He and [John] Lackey used to have a saying," Ross said. "Their saying was: 'Never lost with 12 runs and air-tight defense.' So, I texted him, 'Jon, you ever lost with 18 and air-tight D?' His response said it was still undefeated. And then I texted, 'Nice homer.'

"That was one of those that definitely made me chuckle last night seeing that. That was a bomb, too. He crushed that ball."

Worth noting
• Ross has been trying to balance getting outfielder Ian Happ (.180 average, nine homers, 23 RBIs and a .615 OPS) going with igniting the lineup as a whole. Lately, that has led to Rafael Ortega (.391/.440/.522 in his last 13 games, entering Tuesday) getting more at-bats.

"Happer knows he's working toward something, and he is," Ross said. "I've talked to him multiple times. We had a good discussion [Monday]. Ortega's playing really well right now. ... You need to reward the guys that are playing well."

• Second baseman Nico Hoerner was back in the lineup on Tuesday, following a day off in St. Louis and an early exit on Sunday in Phoenix. Ross said he is still be cautious with Hoerner, who recently returned from a hamstring injury.

"We keep track of yardage and all that stuff and the sprints," Ross said. "And then the hardest one on soft-tissue issues is the travel day on the plane."

Quotable
"He's got real thunder in the bat. He's got a pretty good stroke. I remember he made up this shirt. Remember the Seattle game [in 2016] where he bunted and we won? I've still got my shirt at home -- it's like a sleep shirt. But it says, 'Bunt to win,' with a picture of him squeezing in the winning run." -- Ross, on Lester