What happened: Brendan Donovan began a rehab assignment with the Mariners' Arizona Complex League affiliate, serving as designated hitter and batting leadoff. The assignment opens as Seattle heads into the second half of the season coming out of the All-Star break.

Why it matters: Donovan's activation window comes as the Mariners chase AL West tiebreak positioning down the stretch. Elsewhere in the division picture, left-hander Colton Gordon now pitches for the Astros after Houston's trade sent him out in the deal that moved out a veteran arm to Milwaukee.

What to watch: Watch for Donovan's next rehab outing and whether he progresses toward a big-league activation as the Mariners open the second half.