ARLINGTON -- The Rangers placed first baseman Ronald Guzman on the seven-day concussion disabled list on Tuesday. Guzman must stay out a minimum of seven days and then pass another series of tests before he can be activated.
Gallo sustained the concussion in the sixth inning of Monday night's 7-4 victory over the Padres. He was at third base when Padres catcher Austin Hedges tried to pick him off. Guzman dove back to the bag and was kneed in the head by third baseman Christian Villanueva.
He immediately came out of the game and went into Major League Baseball's concussion protocol.
"Similar to [Jurickson Profar] earlier this year, we want to make sure these guys are completely clear," manager Jeff Banister said. "We want to make sure we pay attention to, be diligent about this and not mess around."
The Rangers recalled utility player Ryan Rua from Triple-A Round Rock to replace Guzman. This will be Rua's fifth tour with the Rangers.
The club also once again passed over outfielder Willie Calhoun, who is hitting .301 in his past 48 games. He has been used strictly in left field while Rua can play multiple positions.
"Right-handed bat, versatile, can play first base and can play the outfield," Banister said. "We are in that time of the year moving into the All-Star break where guys have gone at it hard, the heat, we have a number of guys who are feeling the effects of playing. Rua gives us the most versatility to help these guys out."

Nomar Mazara started as the designated hitter on Tuesday after leaving Monday's game with tightness in his left hamstring. Joey Gallo, who was in left field, is also dealing with a sore left hamstring. Profar made his first start at first base since Sept. 19, 2016.
Rangers beat
• Backup catcher Carlos Perez, on the disabled list with a sprained right ankle, is taking batting practice and running the bases. Tuesday was the first day he was eligible to be activated off the DL, but the Rangers have not made that decision yet.
• Martin Perez threw five scoreless innings for Class A Hickory against Augusta on Monday night in his first start on a rehab assignment. He allowed two hits, did not walk a batter and struck out nine. He threw 51 of 59 pitches for strikes. He'll return to Arlington and throw a bullpen session on Wednesday before the Rangers decide where he'll pitch next.

• Keone Kela's save on Monday made him 19-for-19 in save opportunities to start the season. That matches Francisco Cordero in 2004 for the club mark to begin a season.