DETROIT -- The Tigers’ decision to option lefty reliever Blaine Hardy on Friday caught many by surprise, given his importance to Detroit’s bullpen over the last couple seasons. The diagnosis that came out of Hardy’s visit with noted orthopedist Dr. James Andrews caught few off guard, given the issues he has pitched through this year.

Hardy’s season is effectively over after Dr. Andrews recommended Hardy address the left forearm and elbow pain that has bothered him at various points this season. Hardy will undergo a platelet-rich plasma injection to aid in healing, a process that would sideline him for six weeks.

The injury is likely to end up with Hardy on the injured list in Detroit, nullifying the option to Triple-A Toledo.

The Tigers announced Friday that Hardy was seeking a second opinion from Dr. Andrews, having undergone an MRI exam on his arm early in the season. Hardy spent about three weeks on the injured list in April and May with what was called a left forearm strain.

Though Hardy has been pitching through elbow inflammation, his versatility has been greatly limited. He has just five two-inning appearances since his previous IL stint, and he pitched on back-to-back days only once before he pitched three consecutive days last week thanks in part to the Aug. 6 doubleheader against the White Sox.

“We really didn’t push it too much; multiple innings maybe once or twice,” manager Ron Gardenhire said. “It was only when he said, ‘I feel good, I’m fine, I can go back out.’ We knew what we were playing with, an elbow that got some soreness in it. It started in Spring Training, and we knew we weren’t going to be able to extend him out [as a starter].”

Hardy finished with a 4.47 ERA in 39 relief appearances, allowing 38 hits over 44 1/3 innings with 13 walks and 29 strikeouts. While his strikeout rate dropped to a career-low 5.9 per nine innings, his rate of two home runs per nine innings was a career high.

While Hardy's average exit velocity of 84.8 mph placed him among the top three percent of pitchers in the league, and his hard-hit rate put him in the top seven percent, opponents hit Hardy harder than the metrics would suggest.

Though surgery was an option, it would’ve sidelined Hardy for at least part of next season. It would’ve been a difficult situation for an arbitration-eligible reliever who turns 33 next March. If the PRP treatment works, Hardy will not only be healthy, he’ll have a Minor League option remaining.

Stewart nearing second rehab assignment

Outfielder Christin Stewart appears to have made progress again as he works through Major League Baseball’s concussion protocol. The rookie slugger took batting practice on Tuesday, according to Gardenhire, and he could soon go back on a rehab assignment at Triple-A Toledo.

“He has to go through one more test before he does that,” Gardenhire said. “If that’s clear, then he’ll go to Toledo and start playing, and then we’ll see where he’s at after five days.”

Stewart went 1-for-11 in three games for the Mud Hens last week before being recalled from his rehab assignment and going back into concussion protocol, having shown symptoms in another test.

Quick hits

• Niko Goodrum became the third Tiger to start in center field in four games since JaCoby Jones’ season-ending left wrist fracture last Thursday, joining Victor Reyes and Harold Castro. That mix is likely continue for the foreseeable future, at least until rosters expand in September.

• Goodrum brings 3,000 cases of water to Flint

• Beau Burrows, the Tigers' 14th-ranked prospect according to MLB Pipeline, allowed three runs on five hits in five innings Sunday for his second Triple-A win at . Detroit’s first-round Draft pick in 2015 owns a 2-5 record and a 5.05 ERA with the Mud Hens.