OAKLAND -- When the A’s signed Marco Estrada to a one-year deal in the offseason, they knew the 35-year-old's success with Toronto that featured an All-Star appearance also came with a history of back issues that could limit his workload over the course of the season. Estrada will miss at least one start after the club placed him on the 10-day injured list on Wednesday with a lumbar strain.

“We were hoping we could get a certain amount of starts out of him,” A’s manager Bob Melvin said. “We knew 30-plus starts were not going to be realistic, and from time to time we would have to do this with him.”

Estrada is 0-2 with a 6.85 ERA and a .242 batting average against in five starts. He pitched well in his first three outings, posting a 2.76 ERA, but he took the loss in each of his last two starts as he allowed 13 runs on 14 hits in 7 1/3 innings.

The lower back issue was something Estrada said he had been managing since Spring Training, but the problem began to flare up before his start in Baltimore last week.

“I didn’t want to say anything,” Estrada said. “I was kind of hoping for a miracle that it would just go away. I did all my work, tried everything.”

Estrada struggled against the Houston Astros on Tuesday night in what was his shortest outing of the season. The right-hander was roughed up for a season-high seven runs in just 3 1/3 innings. He surrendered two home runs and is now tied for most homers allowed by an American League starter with seven, but the sign that led Melvin to believe Estrada’s back issue had worsened was the lack of command -- he walked a season-high three batters and hit another.

“Usually he knows where the ball is going,” Melvin said. “It looked like it was a little bit of a fist fight for him in where he was throwing the ball, and a lot of that has to do with health. It doesn’t make sense running him out there if he’s not feeling great.”

The A’s will send Estrada to see a back specialist on Friday, and the hope is that he will be good to go once eligible to return.

“We’re trying everything,” Estrada said. “When I’m healthy, I know I can still pitch and help this team win. Right now, I’m not helping and it’s hurting the team.”

Bassitt rejoins A's

Taking Estrada’s spot on the roster was right-hander Chris Bassitt. Recalled from Triple-A Las Vegas, Bassitt is expected to start in place of Estrada on Monday against the Texas Rangers, but Bassitt's ability to pitch out of the bullpen allows Melvin some flexibility.

“He’s probably done his best work in the last year and a half,” Melvin said. “Kind of tightened up his mechanics some, has good movement and throws hard. He’s a good guy to have here.”

Bassitt began the season on the injured list with after taking a liner off his right knee during an appearance in the A's second exhibition game against the Nippon-Ham Fighters in Japan last month. He found himself in the mix for a rotation spot this spring, coming off an impressive 2018 campaign that saw him go 2-3 with a 3.02 ERA in 11 games, seven of which were starts.

After undergoing Tommy John surgery in 2016, it took a while for Bassitt to regain his velocity. That seemed to return in the spring when he showcased a fastball that was touching 97 mph. Already possessing a 70 mph curveball, the uptick on his fastball gives Bassitt a nice variation of speeds to keep hitters off balance. He carried that into his Minor League rehab assignment, combining to post a 3.27 ERA and holding opponents to a .190 average in three starts.

“Some guys it takes a while to get all your stuff back after an injury like that,” Melvin said. “I think he’s more confident than he’s ever been to this point. He no longer worries about health now. It’s all about producing.”