With ace Jered Weaver possibly returning soon from the disabled list, Los Angeles Angels manager Mike Scioscia will have to figure out who's going to be the odd man out in his rotation.
After what Ervin Santana just did, it could be rookie Garrett Richards.
Richards faces the Arizona Diamondbacks for the first time Sunday when the Angels try to win their sixth consecutive interleague home series and move a season-high five games above .500.
Out since May 29 with a lower back strain, Weaver appears to be recovering nicely after throwing a pain-free 60-pitch simulated game Friday.
The right-hander is scheduled to have a bullpen session Sunday when Scioscia said the team will "make a determination of exactly where he is."
For now, Richards (1-0, 1.38 ERA) is in the rotation as he gets set to make his third straight start in place of Weaver.
But after Santana's one-hitter in Saturday's 2-0 victory, it's uncertain how long the rookie right-hander will keep taking the ball.
Possibly pitching for his spot in the rotation after going 1-1 with a 10.18 ERA in his previous four outings, Santana retired the first 20 batters he faced - Justin Upton broke up the perfect game with a single - as the Angels rebounded from Friday's 5-0 series-opening defeat.
"If (Santana) commits, that's what he can do," Scioscia said.
The Angels (35-31), winners of 27 of 39 against NL teams, have not lost a series at home during interleague play since June 14-16, 2009, against Milwaukee.
Richards will try to keep it that way. In his last outing, he did not earn a decision after walking a career-high five in five innings of Monday's 3-2 road win over the Los Angeles Dodgers.
The Diamondbacks (32-33), losers of six of eight to the Angels, close out their six-game trip with Ian Kennedy (5-6, 4.32) on the hill.
The right-hander needs to improve after surrendering a season-high 10 hits and six runs in Tuesday's 9-1 loss at Texas. He had an 0.66 ERA while winning each of his previous two outings.
Kennedy, who is 0-3 with a 10.91 ERA in his last three interleague starts, will face the Angels for the third time, and first in a Diamondbacks uniform.
In his only start against the Angels, the right-hander was tagged for five runs in two innings of a 10-5 New York Yankees road loss Aug. 8, 2008.
It is the shortest of Kennedy's 90 career starts.
Albert Pujols, 1 for 3 with a double off Kennedy, could return to first base Sunday. He went 0 for 4 as the DH on Saturday after fouling a ball off his shin in the series opener.
Center fielder Peter Bourjos is expected to make his first start for the Angels since June 6 on Sunday.
Angels right fielder Mark Trumbo is batting .386 with seven homers and 20 RBIs in Anaheim after hitting a two-run shot Saturday - his team-leading 15th homer.
Upton is hitting a team-best .366 as the Diamondbacks have a 7-4 record against the AL in 2012.
The Angels have won 11 of their last 12 interleague series.