BOSTON — If things had worked out the way the Boston Red Sox desperately wanted – however unwarranted – they would keep third-base prospect Rafael Devers in Double-A Portland, developing his game, while two-time All-Star third baseman Pablo Sandoval would handle the job in Fenway Park.

Sandoval was on script in March, batting .338 with five home runs in 21 exhibition games.

“We were all optimistic he was going to have a bounce-back year,” Boston Manager John Farrell said. “He was motivated. He was driven. He knew he had to go out and perform. As spring training unfolded, we thought this was happening.

“Unfortunately, it didn’t.”

It certainly did not.

The Red Sox on Friday designated Sandoval, 30, for assignment, the first step in releasing him. It was a drastic step, financially, because Boston still owes him $48.5 million from the $95 million contract he signed before the 2015 season.

At the same time, Boston promoted Devers from Portland to Triple-A Pawtucket – a step away from the big leagues.

“I’m not counting on Devers at this point,” Red Sox President Dave Dombrowski said.

“We think Rafael Devers is going to be a very, very good player. But I don’t want to put it on his back that we’re counting on him in a pennant race. He should go to Triple-A and play like he’s capable of playing, and we’ll see what takes place at that time.”

In other words, Devers could be contributing to the Red Sox as early as next month if he continues to rake like he did in Portland (.300 average and .944 OPS, with 18 home runs).

“When he makes contact, the ball jumps off his bat,” Dombrowski said.

For now, Deven Marrero and Tzu-Wei Lin will continue to platoon at third base. Brock Holt may also be an option, with his rehab assignment coming to an end by July 20 or sooner.

Even if Devers does not contribute this year, the Sox knew they had to let Sandoval go.

Not only was he batting .212 with a .622 OPS and four home runs, his fielding was subpar, with five errors in 29 games at third. According to fangraphs.com, of all American League third baseman with at least 200 innings played, Sandoval ranked 18th out of 20 on defense, having cost the Red Sox six runs.

Sandoval always played heavy, but he seemed slower in Boston. Farrell admitted that Sandoval’s defense was a key reason for his release.

“Hitters go through ups and downs. You live with that ebb and flow,” Farrell said. “But the constant for guys is the defensive side. (Sandoval) was inconsistent – and unfortunately it would show up at key moments. And I’m not just talking about range, but I’m talking about making the plays you’re asked to make.”

This was not the player then-general manager Ben Cherington thought he was getting. Sandoval was a clutch hitter for the San Francisco Giants, playing on three World Series title teams with a World Series average of .344 (18 points higher than Babe Ruth’s).

On the negative side, Sandoval’s overall numbers were trending down from a high of .330/.943 in 2009 to .279/.739 in 2015.

But Boston was desperate for a third baseman after the 2014 season, coming off a last-place finish, with Will Middlebrooks no longer a contributor. And, maybe, the marketing-crazy Red Sox liked the idea of promoting the “Panda.” They signed him for five years, with an option for a sixth.

Sandoval played 161 games for the Red Sox and hit .236. Boston paid Sandoval almost $700,000 for each one of his 136 hits.

Dombrowski said conversations with owners John Henry and Tom Werner about Sandoval began “a few weeks ago.

“You’re talking about a lot of money,” Dombrowski said. “You’re always hoping the player bounces back.

“He’s worked hard. We just didn’t see the skills there.”

Dombrowski, not surprisingly, didn’t find any team willing to trade for Sandoval. He called Sandoval during the All-Star break and asked him if he would agree to playing more games in Triple-A Pawtucket.

“He had no interest in doing that,” Dombrowski said.

So, the Red Sox parted ways with him.

“What it boils down to is pretty simple: trying to put the best team on the field every night,” Farrell said. “We’ve acknowledged the performance of Lin and Marrero to date. You can’t deny their contributions.”

Both players bring solid defense to the position. The right-handed hitting Marrero, 26, is batting only .225, but .361 against lefties. Lin, 23, bats left and is hitting .333/.871 in 15 games since being called up from the Sea Dogs on June 24.

Sandoval’s release assures that Lin will remain with the major league team, for now.

“I’m happy,” Lin said about Boston’s confidence in him. “I’m still a little nervous. I just want to keep doing my job, you know? Just help the team.”

Will Devers get a chance to help? Dombrowski, who has bumped players straight from Double-A to the majors, said Devers is a different case.

“Our guys feel with his age (20) and where he is, it would be beneficial for him to go to Triple-A and see how he adjusts” Dombrowski said.

Dombrowski did not rule out trading for a third baseman, but said it was not a necessity.

“There are different alternatives inside the organization,” he said. “Again, Marrero and Lin have done very well for us. We’ll keep an open mind and see what happens.”

Kevin Thomas can be reached at 791-6411 or:

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Twitter: ClearTheBases