In three starts dating back to a May 25 game against the Mariners, Santana (2-7) has an ERA of 10.43, allowing 17 runs and 14 walks in 14 2/3 innings. His seven losses for the Angels (31-29) put him in a tie for second in the league.
"He just hasn't unlocked that delivery that's going to let him repeat pitches," Angels manager Mike Scioscia said following Santana's last start. "He's not throwing the ball anywhere near his potential right now."
Rockies starter Christian Friedrich (4-1), on the other hand, has earned wins in each of his last three starts. In his last outing against the D-backs, the left-hander tossed seven scoreless innings, giving up four hits and two walks.
After just five starts since he was called up from the Minors and debuted on May 9, Friedrich already leads the Rockies (24-34) in wins with four.
But still, the rookie feels he can be better.
"I've had worse records with better stuff than I'm throwing right now," Friedrich said following his last start. "[Personal] wins are nice. But as long as the team gets the win, that's the most important part."
Angels: Hunter thriving in the two-hole
Following a game on Friday night in which he drove in six runs on two home runs and a single from the two-hole, Torii Hunter came back on Saturday with another strong performance. He went 3-for-4 with a walk and three runs scored.
"The way he performed [on Friday] in the two-hole, we want to keep that look," said Scioscia said after Friday's game.
"Torii is a guy who'll work some counts, he runs well, he creates offense. He's not a traditional two-hole hitter, but I think having him in front of Albert [Pujols] and Mark [Trumbo] is something that can work."
In his first appearance since coming off of the disabled list, Angels reliever LaTroy Hawkins tossed two-thirds of an inning on Saturday, giving up no runs on one hit while striking out one.
He missed the last 30 games after fracturing a finger on his right hand while fielding a ground ball on the last play of the game against the Blue Jays on May 6.
Rockies: Losing streak extended to four games
After winning seven of eight games to cut their deficit in the National League West to 9 1/2 games, the closest they had been since May 17, the Rockies have lost four in a row.
They have surrendered 34 runs during the streak, while scoring just eight. Only one Rockies starter has gotten out of the fourth inning during the last four games.
While the Rockies are 0-5 to begin Interleague play this season, the Angels have started 3-2, with their two wins against the Rockies giving them their first Interleague series victory of 2012.
After winning all six series against the NL in 2011, the Angels have now won 10 of their last 11 series in Interleague play dating back to 2010.
The Angels have also won their last eight road games for the first time since winning eight consecutive away games from July 18-Aug. 2, 2009. They have won 13 of their last 17 games overall and have cut the Rangers' lead in the American League West to three games, the closest they've been since April 12.