MLB Player News

Diaz (shoulder) threw a bullpen session Tuesday, Mike Puma of the New York Post reports.

Diaz threw 21 pitches during his mound session, and manager Carlos Mendoza said afterward that there is a good chance the 30-year-old reliever begins a rehab assignment in the minors Thursday. It's unclear how many minor-league reps the Mets will give their star closer, but the fact Diaz is already able to begin an assignment likely signals that he will only require a minimum-length stint on the IL.

Hoeing (hamstring) is set to throw a live BP session at Single-A Jupiter this week, Christina De Nicola of MLB.com reports.

Hoeing reported tightness in his hamstring during a rehab appearance in late May. After a couple of weeks off, Hoeing is working his way back to pitching in games, with a live BP session being one of the final steps before resuming his rehab stint.

Simpson (elbow) has started throwing, Christina De Nicola of MLB.com reports.

Simpson has been shut down since April, when he underwent surgery to repair the ulnar nerve in his left elbow. However, he's begun throwing at Single-A Jupiter. He's on track to return in late July or early August.

The Marlins outrighted Go to Triple-A Jacksonville on Tuesday.

Go was designated for assignment last week and after clearing waivers, he'll stick around in the Marlins organization at Jacksonville. The 25-year-old owns a 3.00 ERA in nine innings with Jacksonville and has yet to make his MLB debut.

The Cardinals recalled Roycroft from Triple-A Memphis on Tuesday.

The right-hander was optioned to Memphis in late May but is now back with the big-league club. Roycroft has given up four earned runs in six innings for the Cardinals this season but has a 0.98 ERA over 14 outings at Triple-A.

The Pirates selected Heller's contract from Triple-A Indianapolis on Tuesday, Alex Stumpf of MLB.com reports.

Heller had posted a 4.91 ERA but also a 34:8 K:BB over 18.1 innings with Indianapolis. The 32-year-old has extensive major-league experience, having collected a 3.06 ERA over 50 career appearances covering parts of five seasons.

The Pirates optioned Hernandez to Triple-A Indianapolis on Tuesday, Alex Stumpf of MLB.com reports.

Hernandez hadn't pitched in nearly two weeks after being recalled back on May 23 and making an appearance that day. He's being replaced on the roster and in the bullpen by Ben Heller.

The Cardinals optioned Loutos to Triple-A Memphis on Tuesday.

St. Louis is swapping out right-handed relievers, replacing Loutos with Chris Roycroft. Loutos contributed 1.1 scoreless innings over two appearances during his brief time in the majors.

Atlanta transferred Matzek (elbow) from the 15-day injured list to the 60-day IL on Tuesday, Grant McAuley of 92.9 The Game Atlanta

The transaction frees up a spot on the 40-man roster for infielder Brian Anderson, who signed a one-year deal with the club. Matzek has been sidelined for nearly a month with left elbow inflammation and now won't be eligible to return for at least another month.

Walston is scheduled to start Tuesday's game against the Giants at Chase Field.

After he was called up from Triple-A Reno on May 26, Walston made his first big-league start later that day against the Marlins, striking out four over 4.2 scoreless innings in a no-decision. Arizona had previously confirmed Walston for a start against the Mets this past weekend, but he was ultimately pushed back in the pitching schedule after the Diamondbacks elected to call up Slade Cecconi from Reno to slot into the rotation following Zac Gallen's (hamstring) placement on the 15-day injured list. Until one of Gallen, Merrill Kelly (shoulder) or Eduardo Rodriguez (shoulder) returns from the IL, the Diamondbacks should have back-end rotation spots available for both Walston and Cecconi.